# PAR v. WPG?



## Dryn

I've been doing a lot of research on light theory and how it pertains to lighting in an aquarium. My wife says way to much... anyway, I've been studying how light works, how it is measured, and how plants use it. I've found out that plants don't "see" light the way we do. We see "green" light best and they "see" "blue" and "red" light the best. Therefore, any current measures of light are not that usable in regards to plants (lumens, lux, flux, CRI, color temp., etc.). This has led to hobbyist simply using the x-number of watts per gallon of water as a general guidline for their aquarium systems. However, light "intensity" decreases as it gets further away from the light source (inverse square law) and various parameters can greatly influence the amount of light entering the tank (cover glasses, dirty water, water turbulence, backgrounds, etc.). Not to mention, that not all "watts" are equal anyway. So, basically, the WPG rule is quite unusable without considering these parameters. Therefore, I set out to find a better way to measure light for plants. I found out that plants absorb light within a set range of nanometers, called Photosynthetically Active Radiation (measured in microEinsteins/m^2/s), and it is measured with a PAR meter. This intrigued me. Quite simply PAR meters measure the amount of usable light a source gives off in reguards to plants. But, how can we use this? PAR meters are quite expensive. There are some ways to calculate the PAR range through advanced math equations and a lot of estimation based on somewhat inaccurate measurement, but that is what we have to deal with. So, I did what I do best, and scoured the net and various books for every shred of data I could find on PAR measurements and actual tank readings. I compiled the hundred or so light readings and several dozen tank reading together and made some estimates.

Basically, I found that a given light source will give off between 1.0 PAR for cheap T8 lights and 1.4 PAR for good, high-tech lights like T5 and HO. Metal Halides and their like give off between 1.4 and 1.7 PAR. This is quite variable, but can be used as a "loose" estimate of how much PAR a source can be expected to give off.

In order to make use of this estimation, we must know how much light our plants need. I found a lot of conflicting data (which shows how adjustable plants can be) but came up with a range of values: 15-80 PAR for low light plants, 50-150 PAR for moderate light plants, 100-200+ PAR for high light plants.

Now we know how much PAR a light _could give off and a range of values plants could use. Yet when I checked against actual reading, the values were off quite a bit. Why? Well, reflectors played a huge part. Having no reflector could reduce output by 75%. Good, parabolic reflectors could give from 200%-350%+ more output if they were very, very good (parabolic, mirrored, and around every individual light). Now I was getting somewhere. Unfortunately, light entering the tank, reflecting off the glass, and being absorbed by the background all contributed to variations in my calculations v. actual readings.

There is just too many variations to calculate for the average hobbyist. However, I did notice that a good, aquatic plant specific light system averaged about 300% increase in Watt/PAR value and the average reduction on light entering the water was about 40%.

So, we take the watt rating, multiply it by the PAR factor (1.0-1.4) and get the PAR rating at the source. Then we multiply by the reflector factor (~300%) and divide by the light loss at the surface (40%). Then we have a pretty decent estimate of the amount of PAR actually getting into the tank. This calculation has proven itself to be off by as much as 10% which makes it unscientific, but still relevant to the average hobbyist.

The PAR of light actually in the tank bounces around a lot, but for all intents and purposes, it pretty much gets reduced at a steady pace. (Inverse square law). So, to use our PAR value, we need to see how much is reduced for each tank size.

An optimal "low light" tank is going to need about 50 PAR at the substrate level.
An optimal "moderate light" tank is going to need about 100 PAR at the substrate level.
An optimal "high light tank" is going to need about 150 PAR at the substrate level.

Therefore, (because of the inverse square law)

12 inch tank: low -80 PAR at the surface
moderate -166 PAR at the surface
high -250 PAR at the surface
24 inch tank: low -166 PAR at the surface
moderate -333 PAR at the surface
high -500 PAR at the surface

Using this method, we can get a rough estimate as to whether or not we are providing enough light and therefore, how much to increase/decrease and how many nutrients to add/subt.

It isn't perfect, and it takes some calculations, but I think it is better than the wpg rule.

Please tell me what you think. I look forward to any discussion about my theory. I especially look forward to talking to anyone with access to an actual PAR meter._


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## Philosophos

PAR is the way things are headed. Quantum par meters run about $300 each, though.

Output in mmol PAR should be something aquarium lighting companies print on their box. They've already got the equipment hanging around. I'm sure most companies would rather do it them selves than someone doing published reviews that directly compares them to all of their competitors.

Plants don't exactly have high light requirements from what I understand. Amano grows HC at <50mmol PAR. Distribution is usually more of an issue, and that's effected by how you lay your lighting out.

-Philosophos


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## Dryn

Distribution is definitely the key. Yeah, Amano doesn't use a lot of light, but he is more interested in the long-term welfare of his plants. He doesn't want to drive growth to the max. Plants tend to look better when grown slowly anyway. He not only uses low light levels, but he also uses inefficient green phospher coatings in his lights which lower the amount of usable PAR even more.


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## Philosophos

I like the green spectrum; I'm thinking on changing to eventually. Green is forgiving; small imperfections get washed right out. 

Having a tank with Ludwigia that can grow .5-1'' a day at its prime makes me not want high growth so much anymore.

-Philosophos


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## davemonkey

Dryn, your research is very interesting. I have a hard time following the math of it, but I'm figuring I've got enough light for moderate-light plants based on WPG and on PAR.

18" tall tank, 130 watts PC, decent reflectors, no top/cover on the tank.

As to green light, I'm not fond of it at all. I used to say I liked "natural" looking light, but I've noticed that sunlight seems very yellow to me. I prefer a crisp, clean white light that doesn't visually alter any colors in my tank. If I had to pick some color, I'd go with just a touch of purple to give a subdued look, but just a touch.

-Dave


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## Philosophos

Sunlight is quite yellow out of water, so cleaner colors can be perfect if you're trying to make your tank look like a terrestrial scene on a clear, bright day. Usually this lends its self to iwugami, which isn't my style. For simulating areas under a forest canopy, or underwater, blue/green is the way to go.

Purple sounds interesting. Do you happen to have any pictures hanging around of a good scape with a touch of purple? For some reason my mind goes right to black lighting, glowfish and pink gravel.

-Philosophos


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## davemonkey

Philosophos said:


> ...purple? For some reason my mind goes right to black lighting, glowfish and pink gravel.
> 
> -Philosophos


You guessed my next scape!! ound:

Seriously, though, that's not quite what I meant. The sticky "9325K The difference" has a good shot of what that bulb looks like compared to others, and has some combos. While the 9325 is a bit pink for my taste, I thought it looked good mixed with another bulb. It gave some of the color-popping characteristics of the 9325, but more realistic color rendering with a somewhat subdued look. To me it looks kinda purple.

I'm not sure which bulb combo it is (I can't see attached images from my work computer), but it's in that thread somewhere.

-Dave


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## Dryn

Purple? quite retro. Plants don't see ultraviolet. Could make a cool deep-water style out of one though. Maybe with some actinic in the back to add more depth.


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## Dryn

Davemonkey: Here is the formula.

Watts (130) X PARvalue (1.4 b/c good light) = 182 PAR 

182 x 300% b/c good reflectors = 546 PAR at the source 

546 - 40% scatter b/c of the surface = 328 PAR at the top of the tank 

328/2 at one foot = 164 PAR @12"depth
164 / (1/4) = 123 PAR at the substrate b/c inverse square law.

By my calculations you should have around 123 PAR at the substrate level of your rank which should be plenty for moderate light plants and maybe enough to keep some high light plants alive and growing slowly at the substrate level.


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## Philosophos

Wow, GE9325/6700K does some nice stuff. I've never liked the 9325K on its own; greens get lost.

Is there such a thing as a single bulb CF GE9325/6700K?

-Philosophos


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## Dryn

There are CF bulbs that have one color on one side and another color on the other. I don't know what those two colors are. They are probably close to that but aren't as "perfect" in color rendering.


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## davemonkey

9325 with 6700K, I'd certainly buy some. They aren't available that I know of...yet. There are 6700K/10000K and then some actinic mixes, though. 

Philosophos, if you like the green, I had the 6700/10000K bulbs from coralife and they did put out alot of green light. I think most all coralife and saltellite bulbs do.

Dryn, I was off on the formula, but somehow I got close to what you calculated for me. Thanks.  That seems to be an accuarate formula as far as I'm concerned. I have mostly mod-light plants that do well and a couple species of high-light. 

-Dave


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## TAB

you have to remember that PAR changes over time. Halides for example, gain PAR over the 1st month or so, then they steadly lose it. fluorescent tend to just go down hill.

Then there is color shift.


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## Philosophos

Dave, 10,000K/6700K is exactly what I'm using right now. At 3wpg, I'm still finding it rather crisp and intense. Maybe I should take a look at straight 10,000k.

Color shift and drop in PAR isn't so bad, so long as you change the bulbs regularly. One thing most people don't realize is that most electronic timers will burn out CF faster. I've seen warnings on the osram/sylvania website about it. 

-Philosophos


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## Supercoley1

Was a great read and pretty good assesment BUT the most important aspects (IMO) have been missed 

The output of the light at source is not really that much use to this hobby!!

Some people who have 3WPG may not have as good light as someone with 1WPG purrely due to the spread of light. Simple differences in positioning, height, reflector angle etc.

For example people assume raising the light away from the surface = less light BUT it can improve spread which actually increases light. This is within reason of course but the difference between having your light 3-4 inches above the water surface and it being 8-12 inches above the surface can mean much improved growth especially at the substrate.

What we need to measure with light is PAR or PUR at the target and not source. Having great light at output/source does not mean great light at target and from testing I have read about there can be huge differences (as much as 200-300PAR at surface down to 30-40 at substrate) from water surface to substrate with no shading in standard 12" tall tanks!!!

I think people should get away from the 'low light/high light' plant theory too. As you quite rightly state Amano uses a lot less light than most people think and most definately less than the Fitch articles suggest he does however the units labelled ADA are 'specced' to be high light whilst actually producing lower PAR. Gets them using Amano levels whilst satisfying the ADA lovers that think high light is the goal :lol:.

If you think about it and going along with your initial post light at the substrate is less due to the further distance but then why do we suggest HC, Glosso and the like are 'high light' plants. Also how do the ADA unit users (who have less light than they think) manage perfect carpets of HC in their tanks? My answer although theory rather than test is they are high CO2 tanks and ADA concentrates quite heavily on very good CO2!!!!

On the subject of sunlight. It is my understanding that sunlight is 5500K. The LEDs I have are 5500K and I can state the light is pure white. Looks very crisp and natural. I use green 7500K T8 and pink 4000K T8 on emersed setups and all it does is change the colour of the plants. Putting the same tray of HC green makes HC look the healthiest ever whilst under pink it look like it is struggling a little. Growth is of equal speed under both.

I think what also needs to be looked at along with reflectors are the following:

Type of ballast - Using a magnetic (T5HO will not have magnetic) may mean less light too through efficiencies. Also means the tube will degrade quicker.

Reflectors you have covered pretty well. Very important to have individual reflectors. I don't necessarily agree with the polished statement. Some of the best reflectors I have used have been brushed aluminium. Almost white in colour and they outperformed (looking at plant growth) polished reflectors by a mile!!! Just as important is to regularly clean them. Build ups on the surface will reduce their effectiveness rapidly.

Also small things like water clarity and surface scum can reduce light.

Light testing/calculation is one of those things that for the general hobbyist is either not in a position to do, not interested in etc. WPG is easy. It is the only measurement that is clearly labelled on every tube and packaging (many lights do not state K or Lumens even) so every one can get a very quick number to work out what light they have. I do agree it is so far off the mark it is unbelievable but it is the only workable solution unless manufacturers are going to agree to all put K, Lumens and a PAR reference (say tested 12" away) on their unit.

Even then the manufacturers will exaggerate as they do on all things 

That is why the WPG rule was and is still used. It is one of the most inaccurate calculations you can get BUT it is the only one that ALL users can do.

I've said for a while but may as well say it again. If I were given the choice of 2 x T5HO or 4 x T8 I would go for the T8 every time. They will provide a much better spread because you can spread them out better and get much better coverage and they will actually provide more light per W than the T5HO. T5 will produce more light per W but again I would prefer the T8s to get more tubes and allow better coverage. However I would (and do on my emersed setups) use good reflectors and programmed electronic ballasts (the ballasts that T5HO uses.)

AC


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## Philosophos

Naturally spread and penetration are issues, even with PAR known. By this rational though, we should throw away WPG as well for the exact reason you've stated; someone with 3wpg can have the same PAR as someone with 1wpg. 

We still measure GH even though there's no way of knowing whether its constituents will actually fulfill osmotic pressure requirements. This is almost the equivalent of using lumens.

Hobbyists feed their fish all the time without knowing how closely dietary requirements are being adhered to.

Estimation is an inevitability, but being able to calculate PAR at source, reflector efficiency, and diffusion ranges can give a maximum level of PAR possible, and even help to indicate low range. Taking the next step on WPG is certainly more useful to the average hobbyist than having to buy a PAR meter.

The only issue I'm seeing is people who don't like math. Personally, I don't see a need to always cater to the lowest common denominator. There are things about plants 99% of us will never understand, but the after effects of other people knowing it is certainly beneficial.

-Philosophos


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## Supercoley1

> We still measure GH even though there's no way of knowing whether its constituents will actually fulfill osmotic pressure requirements. This is almost the equivalent of using lumens.


I don't know many people who measure anything!!! let alone something like GH 



> The only issue I'm seeing is people who don't like math.


I am very good at maths and being an ex-accountant I enjoy numbers quite a lot. However I think maths like science limit how open minded people are when suggestions are made as to what they can/should do. People who use maths and science within the planted tank tend to have rigid understandings of what is happening and find it hard to believe that things outside of the calculations/scientific statements can be true.

I think if you are going to go by what the maximum possible PAR is from source then you are no nearer to accuracy than WPG. With WPG you know the max is the wattage and then endeavour to make the best of that wattage. With PAR you know the max PAR and endeavour to achieve the best of that PAR. Both the same IMO.

Like I always say. If you have PAR meter and can measure at targets then you can manoeuver the lights to achieve the best outcome. If not then you can use the free PAR meter as I do - Plants 

Those who like to apply maths to the equation will often end up the same way as those who rely on tests. They get their N, P, K etc readings and up down to that chasing the golden goose egg which then leads to other problems and they get algae filled tanks. Those who don't test and throw unlimited nutrients (or at least a little more than needed) in can move off the defficiency suggestions and spend their time getting the CO2 right.

With light it is simple. 2 x good quality (not necessarily expensive nor aquarium, nor plant specific) T8 lamps with reasonably good reflectors that are the full length of the tank they are above and as long as it isn't ridiculously deep (I mean 3ft+) can grow any plant they want as long as they have great CO2 and good circulation. those who want to get their calculators out are free to do so but they are wasting tank viewing time on something that doesn't really need to be delved into in such depth :lol:

For me I do nothing these days. I am happy enough with light. I am happy I add enough of each nutrient. As plantmass grows I may tweak position of diffuser and/or circulation pump/filter outlet but other than a minor tweak each month or so to keep the flow complete and therefore maintain the CO2 all I do is watch an algae free tank and enjoy watching the fish in their natural looking home 

AC


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## BryceM

Ah, this is an age-old topic isn't it.

There was an interesting article recently in TFH where they took some PAR measurements in aquariums with plastic hang-on backgrounds versus aquariums with the back pane painted. Painting the back panel reduced light intensity inside the tank by a surprising amount.

Simply put, there are far, far too many variables to allow us to predict the intensity of light in a particular setup. Why do we use watts/gallon? Well, that's what is listed on the package. For a given light source and a "standard" tank geometry, it's useful enough to get someone in the ballpark. Beyond that, watts/gallon breaks down very quickly.

A great solution would be to have local clubs buy and share a PAR meter. It's not like you need it every day. The rub is that the lighting system is generally the single most expensive part of a setup and you're usually stuck with what you buy. Most systems aren't modular and don't allow for much flexibility apart from hours/day of photoperiod.

More light is not always better. Plants often do look better when grown at something short of maximum velocity. Deep tanks do have certain issues. It's pretty hard to grow a thick HC carpet three feet down without causing problems higher up (at lest IME). Experience plays a large role here. If I were setting up a tank for a business or in a setting where it always had to look nice, I'd go with relatively low light and undemanding plant species. That sort of tank is easy to keep looking nice over long periods of time.

At home it's more fun to turn on the halides, play around with CO2 and nutrients, and get the more demanding species to do well.


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## Philosophos

Supercoley1 said:


> I think maths like science limit how open minded people are when suggestions are made as to what they can/should do. People who use maths and science within the planted tank tend to have rigid understandings of what is happening and find it hard to believe that things outside of the calculations/scientific statements can be true.


If this is the issue, then they have clearly failed to understand science. If the theory and the empirical evidence contradict each other, then the theory is wrong, or the observation method is incorrect.



Supercoley1 said:


> I think if you are going to go by what the maximum possible PAR is from source then you are no nearer to accuracy than WPG. With WPG you know the max is the wattage and then endeavour to make the best of that wattage. With PAR you know the max PAR and endeavour to achieve the best of that PAR. Both the same IMO.


WPG is an approximation for lack of knowing PAR. How is it possible to be less accurate when one knows PAR at the source rather than pure wattage? I'd consider this a conjunction fallacy.



Supercoley1 said:


> Like I always say. If you have PAR meter and can measure at targets then you can manoeuver the lights to achieve the best outcome. If not then you can use the free PAR meter as I do - Plants


I agree, plants do a wonderful job. Still, if it's about efficiency, I'd like to buy the ideal light for manageable growth with good distribution. The closer we get to being able to calculate this, or measure it, the less dependent we become on trial and error.



Supercoley1 said:


> Those who like to apply maths to the equation will often end up the same way as those who rely on tests. They get their N, P, K etc readings and up down to that chasing the golden goose egg which then leads to other problems and they get algae filled tanks.
> 
> That's a bit of a straw man. How does it follow that finite observation causes observation in the wrong places? I would think incorrect reasoning and ineffective observation is the cause of looking in the wrong place. Also, how do you differentiate between testing and looking in your tank? Both are methods of observation.
> 
> 
> 
> Supercoley1 said:
> 
> 
> 
> Those Those who don't test and throw unlimited nutrients (or at least a little more than needed) in can move off the defficiency suggestions and spend their time getting the CO2 right.
> 
> 
> 
> Yes, it can be done without testing. This does not mean that avoiding testing will lead to a better understanding of your tank. I believe Tom's initial comments were that EI was created for people who are lazy, poor, or living in isolated locations.
> 
> It's testing and observation that allowed for the understanding that CO2 and lighting are the most frequent limiting factor in the first place.
> 
> Testing is also how we know which nutrients induce certain algae.
> 
> 
> 
> Supercoley1 said:
> 
> 
> 
> With light it is simple. 2 x good quality (not necessarily expensive nor aquarium, nor plant specific) T8 lamps with reasonably good reflectors that are the full length of the tank they are above and as long as it isn't ridiculously deep (I mean 3ft+) can grow any plant they want as long as they have great CO2 and good circulation. those who want to get their calculators out are free to do so but they are wasting tank viewing time on something that doesn't really need to be delved into in such depth :lol:
> 
> Click to expand...
> 
> At such depth? It's a one line calculation. The careful observation and calculation of other individuals is what makes it so you can be a consumer of their products, and not have to think about it your self.
> 
> You're using T-8 because some one else took the time to figure out how and why it works.
> 
> Personally, I like trying to figure out the next step; it improves my tank, and the hobby. Out of this concept, new lights can be picked up and estimated more finely than WPG for testing. This line of thinking helps to eliminate dependence on one brand or format of lighting.
> 
> 
> 
> Supercoley1 said:
> 
> 
> 
> For me I do nothing these days. I am happy enough with light. I am happy I add enough of each nutrient. As plantmass grows I may tweak position of diffuser and/or circulation pump/filter outlet but other than a minor tweak each month or so to keep the flow complete and therefore maintain the CO2 all I do is watch an algae free tank and enjoy watching the fish in their natural looking home
> 
> Click to expand...
> 
> Yes, you've got things set up and that's great. Enjoy the hobby as something that requires little thought or effort if that's your thing. Please don't discourage people from asking why and how, though. Anti intellectualism is not what got humanity out of loin cloths, or fish tanks away from kerosene heaters.
> 
> -Philosophos
Click to expand...


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## Dryn

SuperColey1 When I go to lunch, I'll have to reread your posts. But from what I managed to glean through a quick glance is that you're arguing my theory for me. Thanks. Yeah, there are way to many unknown and hard-to-calculate paramaters in a tank for the average hobbyist to calculate. But, we are hardly average hobbyists. If you've managed to follow even 50% of this conversation, I'd say that qualifies you as an above-average hobbyist. As a hobbyist who enjoys this hobby for more than its aesthetic qualities and it interested in not only growing plants but understanding why plants grow like they do, I think that studying PAR and calculating your own PAR and other parameters is just one part of an enjoyable hobby and also functions as a way to understand what is going on in our individual tanks. Yeah, it is hard and probably not 100% accurate, but it is interesting and does produce results that can be educational. My point is to enjoy this hobby and learn as much as possibe.

I'll reread these posts and talk about the parts that have been brought up when I get more time. Until then, thank you for your comments and keep them coming.


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## Dryn

TAB said:


> you have to remember that PAR changes over time. Halides for example, gain PAR over the 1st month or so, then they steadly lose it. fluorescent tend to just go down hill.
> 
> Then there is color shift.


Tab, I hadn't read anything in my research about color shift. It does make sense, however. Something about phospher decay... But, PAR is a measure of radiation in the 400nm-750nm range, and my research indicates that there really isn't that much of a difference in plants usage of photons in that range. Yeah, chlorophyl A and caratenoids (sp) both use more "blue" light and Chlorophyl B uses more red, but if you average them together and then "weigh" them by their value to the plant, only "green" light is _slightly_ less potent than the other colors, but the plants are able to make use of that light, just on a lesser degree. Calculating this would be a monumental waste of time, but if you are interested, look up PUR values and YTP PAR (I think?). They go into detail on this. This is well beyond a subject that is already flirting with way too far.

As far as lights losing and/or gaining PAR over time, we are calculating value that are off by a slight margin anyway. As long as you change bulb on a regular basis (6months) you will come out ok. My intent is just to give another way of calculating light values more precisely than wpg.


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## Dryn

Supercoley1 said:


> Was a great read and pretty good assesment BUT the most important aspects (IMO) have been missed
> 
> The output of the light at source is not really that much use to this hobby!!
> 
> I understand that, but we are trying to find a better measurement than wpg that the slightly above-average hobbyist could use to estimate need and usage. Since we pay for our electricity in watts, bulbs and light systems are based on wattage rating (which are usually off), and none of the other "normal" ways of measuring light ie. lumens, lux, flux, CRI, etc. really apply to our hobby, I fail to see anything that would be better, or more understandable.
> 
> Some people who have 3WPG may not have as good light as someone with 1WPG purrely due to the spread of light. Simple differences in positioning, height, reflector angle etc.
> 
> This measure is an attempt to account for this... my argument is that wpg isn't good enough for the "above-average" hobbyist.
> 
> For example people assume raising the light away from the surface = less light BUT it can improve spread which actually increases light. This is within reason of course but the difference between having your light 3-4 inches above the water surface and it being 8-12 inches above the surface can mean much improved growth especially at the substrate.
> 
> What we need to measure with light is PAR or PUR at the target and not source. Having great light at output/source does not mean great light at target and from testing I have read about there can be huge differences (as much as 200-300PAR at surface down to 30-40 at substrate) from water surface to substrate with no shading in standard 12" tall tanks!!!
> 
> Of course we need to measure PAR/PUR at the target. The question is, how can we without using an expensive PAR meter (that we would need only once) ? The only thing we have is the measurements and calculations of others to give us a "ballpark" guesstimate.
> 
> I think people should get away from the 'low light/high light' plant theory too. As you quite rightly state Amano uses a lot less light than most people think and most definately less than the Fitch articles suggest he does however the units labelled ADA are 'specced' to be high light whilst actually producing lower PAR. Gets them using Amano levels whilst satisfying the ADA lovers that think high light is the goal :lol:.
> 
> I've used TFH magazine to calculate hundreds of amano tanks by light, size, and "target" light value. I've found that Amano never really seems to make any distinction about light value. He has triple Metal Halides with extra flourescent bulbs over four foot tanks with only crypts and anubias in them, and then he has four-bulb flourescents over deep tanks planted with glosso and other "high" light plants. He seems to adjust based on other parameters. Then again, it never says what height the lights are over the tank and that matters a lot.
> 
> If you think about it and going along with your initial post light at the substrate is less due to the further distance but then why do we suggest HC, Glosso and the like are 'high light' plants. Also how do the ADA unit users (who have less light than they think) manage perfect carpets of HC in their tanks? My answer although theory rather than test is they are high CO2 tanks and ADA concentrates quite heavily on very good CO2!!!!
> 
> My point. Our tanks aren't just glass pots under a light system, they're living organisms. There are other parameters that matter. I just think that the above-average hobbyists needs more than a loose guess using the wpg rule. But, in order to guage the amount of light that we want to use, we need a target. I cannot think of anything better than a low/mod/high light parameter. I cannot think of a single plant book that doesn't rate the lighting needs.
> 
> Furthermore, I challenge you to plant some erio. or glosso in a 24in deep tank with only one flourescent bulb over it and add as much CO2 as you possibly need to achieve any  rate of growth.
> 
> On the subject of sunlight. It is my understanding that sunlight is 5500K. The LEDs I have are 5500K and I can state the light is pure white. Looks very crisp and natural. I use green 7500K T8 and pink 4000K T8 on emersed setups and all it does is change the colour of the plants. Putting the same tray of HC green makes HC look the healthiest ever whilst under pink it look like it is struggling a little. Growth is of equal speed under both.
> 
> Ligh color isn't really worth anything to the plants. Yeah, it _can_ alter the growth patterns; blue makes short, bushy plants, red makes long, leggy plants, but no bulb is completely only one color or another, and the plant will compensate a good deal on its own. Color is more important to us. We like to see good green/yellow light ie 5500k.
> 
> In fact, that degree kelvin rating is based on human perception. A group of scientists got together in Europe a few decades ago and polled a bunch of people on what color they thought a light was and then they used that to come up with what we call lumen ratings. Then they used those to compare a "black-body" object under heat until it reached the agreed upon color, took its temperature and viola degrees kelvin was born. The plants couldn't care less. (this study was much more intense and not to step on any toes or anything... it does have value, just not to our plants).
> 
> I think what also needs to be looked at along with reflectors are the following:
> 
> Type of ballast - Using a magnetic (T5HO will not have magnetic) may mean less light too through efficiencies. Also means the tube will degrade quicker.
> 
> Yeah, cheap bulbs suck. You have to put more energy through them to get a similar amount of usable light. This is why they are only worth about 1.0PAR/W. (my data indicates that some are actually less!)
> 
> Reflectors you have covered pretty well. Very important to have individual reflectors. I don't necessarily agree with the polished statement. Some of the best reflectors I have used have been brushed aluminium. Almost white in colour and they outperformed (looking at plant growth) polished reflectors by a mile!!! Just as important is to regularly clean them. Build ups on the surface will reduce their effectiveness rapidly.
> 
> A lot of research has been done on reflectors...
> 
> Also small things like water clarity and surface scum can reduce light.
> 
> Sometimes a great deal, but we cannot calculate those things easily. I just added in a few extra % to compensate. My research hasn't proven me wrong yet... (Not that it was all that accurate to begin with)
> 
> Light testing/calculation is one of those things that for the general hobbyist is either not in a position to do, not interested in etc. WPG is easy. It is the only measurement that is clearly labelled on every tube and packaging (many lights do not state K or Lumens even) so every one can get a very quick number to work out what light they have. I do agree it is so far off the mark it is unbelievable but it is the only workable solution unless manufacturers are going to agree to all put K, Lumens and a PAR reference (say tested 12" away) on their unit.
> 
> WPG wouldn't have been around for as long as it has been if it wasn't easy. But like all things cheap and easy, it isnt' very effective. Of course PAR calculations are much more time-consuming and intense (without a PAR meter) but we're above-average hobbyists, we should be more interested in a better way for doing _everything_! If not, I'd just go buy a painting.
> 
> Even then the manufacturers will exaggerate as they do on all things
> 
> That is why the WPG rule was and is still used. It is one of the most inaccurate calculations you can get BUT it is the only one that ALL users can do.
> 
> I've said for a while but may as well say it again. If I were given the choice of 2 x T5HO or 4 x T8 I would go for the T8 every time. They will provide a much better spread because you can spread them out better and get much better coverage and they will actually provide more light per W than the T5HO. T5 will produce more light per W but again I would prefer the T8s to get more tubes and allow better coverage. However I would (and do on my emersed setups) use good reflectors and programmed electronic ballasts (the ballasts that T5HO uses.)
> 
> This would definitely be my choice as well. However, T5 are much cooler-looking. Interestingly enough ODNO T8 have a PAR/W rating nearly as high as MH lights!
> 
> AC


Thanks for the conversation. It was a _good _conversation. You still haven't convinced me that wpg is better. Yeah it is easier, but the whole point is to be better. You cannot doubt that figuring out your system's PAR reading didn't give you a better understanding of what is happening to your light than the old wpg standby?


----------



## Dryn

Sorry about the last clip, it sorta merged my comments with his. I was going for separate boxes, but alas, that was not to be...


----------



## Dryn

Philosophos said:


> Naturally spread and penetration are issues, even with PAR known. By this rational though, we should throw away WPG as well for the exact reason you've stated; someone with 3wpg can have the same PAR as someone with 1wpg.
> 
> We still measure GH even though there's no way of knowing whether its constituents will actually fulfill osmotic pressure requirements. This is almost the equivalent of using lumens.
> 
> Hobbyists feed their fish all the time without knowing how closely dietary requirements are being adhered to.
> 
> Estimation is an inevitability, but being able to calculate PAR at source, reflector efficiency, and diffusion ranges can give a maximum level of PAR possible, and even help to indicate low range. Taking the next step on WPG is certainly more useful to the average hobbyist than having to buy a PAR meter.
> 
> The only issue I'm seeing is people who don't like math. Personally, I don't see a need to always cater to the lowest common denominator. There are things about plants 99% of us will never understand, but the after effects of other people knowing it is certainly beneficial.
> 
> -Philosophos


Thanks Philosophos, my point exactly. I would and have done numerous calculations about all sorts of things just for the enjoyment of doing so, and I don't even like math that much. I'd do it again, and again, and again... just to recheck my work. It is part of the fun of a hobby. If that isn't for you, then don't do it. I put on this post just to read other's reactions and thoughts. I've already done the math...


----------



## Dryn

Supercoley1 said:


> I don't know many people who measure anything!!! let alone something like GH
> 
> I am very good at maths and being an ex-accountant I enjoy numbers quite a lot. However I think maths like science limit how open minded people are when suggestions are made as to what they can/should do. People who use maths and science within the planted tank tend to have rigid understandings of what is happening and find it hard to believe that things outside of the calculations/scientific statements can be true.
> 
> I think if you are going to go by what the maximum possible PAR is from source then you are no nearer to accuracy than WPG. With WPG you know the max is the wattage and then endeavour to make the best of that wattage. With PAR you know the max PAR and endeavour to achieve the best of that PAR. Both the same IMO.
> 
> Like I always say. If you have PAR meter and can measure at targets then you can manoeuver the lights to achieve the best outcome. If not then you can use the free PAR meter as I do - Plants
> 
> Those who like to apply maths to the equation will often end up the same way as those who rely on tests. They get their N, P, K etc readings and up down to that chasing the golden goose egg which then leads to other problems and they get algae filled tanks. Those who don't test and throw unlimited nutrients (or at least a little more than needed) in can move off the defficiency suggestions and spend their time getting the CO2 right.
> 
> With light it is simple. 2 x good quality (not necessarily expensive nor aquarium, nor plant specific) T8 lamps with reasonably good reflectors that are the full length of the tank they are above and as long as it isn't ridiculously deep (I mean 3ft+) can grow any plant they want as long as they have great CO2 and good circulation. those who want to get their calculators out are free to do so but they are wasting tank viewing time on something that doesn't really need to be delved into in such depth :lol:
> 
> For me I do nothing these days. I am happy enough with light. I am happy I add enough of each nutrient. As plantmass grows I may tweak position of diffuser and/or circulation pump/filter outlet but other than a minor tweak each month or so to keep the flow complete and therefore maintain the CO2 all I do is watch an algae free tank and enjoy watching the fish in their natural looking home
> 
> AC


You definitely have to be careful about finding answers that are too vague, but doing the calculations and estimates are more about learning about your tank than they are about finding the "golden egg" as you said. I can see how some might think so though.

I'm glad that you are happy with your light. Being happy is the whole point. I like doing the calculations and learning about how light behaves in our tanks. That is part of my hobby. If yours is visual, have fun, send photos, and I'll enjoy your tank too, but these calculations are about doing more. I wouldn't have cared if no one answered the post. I have others that remain unanswered to this day. I was just hoping for some constructive criticism. thank you.


----------



## Dryn

I've got to go now. I'll respond to the other posts tomorrow. I'll also try to bring my some of my data and post it. Feel free to add more comments...


----------



## Supercoley1

Philosophos said:


> If this is the issue, then they have clearly failed to understand science. If the theory and the empirical evidence contradict each other, then the theory is wrong, or the observation method is incorrect.
> 
> WPG is an approximation for lack of knowing PAR. How is it possible to be less accurate when one knows PAR at the source rather than pure wattage? I'd consider this a conjunction fallacy.


It is not that knowing PAR at source is less accurate than WPG. It is that you stop there and then estimate variables from there on which makes it a little pointless. Both mathematical/scientific Calculations will be way off the actual due to the unlimited amount of variables, many known and many unknown/ignored, and therefore you may as well just use the WPG without wasting so much time to get an inaccurate answer. Par at target(s)...very worthwhile if you have the facility. You are now looking at an actual accurate result with no need to estimate anything.



> I agree, plants do a wonderful job. Still, if it's about efficiency, I'd like to buy the ideal light for manageable growth with good distribution. The closer we get to being able to calculate this, or measure it, the less dependent we become on trial and error.


I do not try to suggest that they are failing to understand science at all. Many of the people who fail understand the science but try to apply science to the question too rigidly. They already have the knowledge of 'What is correct'. Where they fail is that they then try to use mathematics and science but have the 'already known' factor already ingrained and then use this combination to get the answer on something with the amount of variables within a planted tank often means that the final calculation is way off the mark. If they were to start with a clean sheet and say to themselves 'everything I understand to be correct or proven may well actually be wrong. I shall ignore what I already understand to be right and assume nothing' then they would be more likely to be able to apply their findings to get the correct answer. While they apply previously understood knowledge to their results then their conclusions may have been swayed.



> That's a bit of a straw man. How does it follow that finite observation causes observation in the wrong places? I would think incorrect reasoning and ineffective observation is the cause of looking in the wrong place. Also, how do you differentiate between testing and looking in your tank? Both are methods of observation.


What I mean here is that observation is a good thing. Testing is a good thing if done with kits/equipment that is known to be accurate. The key is applying the results and coming up with the correct answer. I would suggest 99% of people who use the testing method and then apply those results to their tank from 'knowledge' gleaned from scientific research or even knowledgeable sources like forums can assume the incorrect variable and then are on the 'goose chase' rather than correcting the actual problem.

EI is called lazy man's dosing BUT many of us are not lazy. We use the EI because we are not scared of higher dosing while many (including government scientists still say excess nutrients CAUSE/INDUCE algae. Many people still harp on about Ph crashes caused by CO2!!! We know that many times higher dosing than we do with EI is safe and we know that dosing excess does not cause (or induce as you state) algae. It will feed it but another variable within the tank will have induced it. We also know that PH crash is a theory and that what they really mean is KH crash. We then know that CO2 does not alter KH.

EI was one of the first methods I used when I began on the planted journey. It failed and I blamed it for the failures. I moved onto much leaner methods and assumed that they were better as I got less algae. I failed to take many things into account such as differing plantmasses, lighting amounts, flow, CO2 etc or I corrected the wrong things. I only returned to EI when I had mastered the variables and now it works very well for me. All the other methods work well for me too but that is because I now have the knowledge and confidence to apply to the methods correctly and read the resulting observations correctly.



> It's testing and observation that allowed for the understanding that CO2 and lighting are the most frequent limiting factor in the first place.


I agree but many do understand the correlations between all the parts and can make incorrect assumptions whilst still being much more knowledgable on science / maths than I 



> Testing is also how we know which nutrients induce certain algae.


Exactly which nutrient INDUCES algae? Can't be any of the ones I dose!!! I have no algae in either my hi tec tank (LED lighting, CO2 injected with EI and heavy water changes) nor my non CO2 tank (LED lighting with minimal ferts and no water changes!!!)



> You're using T-8 because some one else took the time to figure out how and why it works.


Thats one hell of an assumption. When did someone else take the time to figure this out for me? I have been one of the people arguing for a long long time about spread and people try to hit me with Lumens statements, that T5HO/CF is a mile better due to intensity, that Amano uses very highlight and put the Finch family article link in when Amano himself admits he uses quite loe light and tests show ADA light units are much lower PAR than expected. It is I (although not alone) that have been saying that T8 is better due to the ability to improved spread/coverage by using more tubes and therefore limiting the 'hotspot/lowspot' problems that can be cause with intense lighting. You know this from the barrreport so I don't know where you think I used other people's advice 

What I mean about knowing the PAR at source only being as good as WPG is that fine you know the exact output of the light on your system with your ballast and your reflector. If you stop there and then try and methemtically/scientifically calculate the variables then you are no better off than with the WPG. However if you are testing PAR through the tank at different target areas you are on the ball and are way ahead of the WPG/PAR at source knowledge. It's fine to know how much light you have over the tank but as you stop there and don't know where the light is distributing, where it is hitting etc and how much is being 'received' then you may as well just put the lights on top, move them about until everything grows well or alternatively use more tubes and spread them out to ensure that you get a closer to equal coverage  I am not pooh poohing science nor mathematics. I am just saying that if we are to test things we need to test the right things. If we want to know how our lights are performing then we need to test the area that we are using them for and not just taking the output.

In the UK we don't have a reliance/compliance with one form of lighting. We pretty much understand light (without PAR meter testing) and compared to the US we tend to use much less light. We tend to focus more on flow and CO2.



> Yes, you've got things set up and that's great. Enjoy the hobby as something that requires little thought or effort if that's your thing. Please don't discourage people from asking why and how, though. Anti intellectualism is not what got humanity out of loin cloths, or fish tanks away from kerosene heaters.


Again you know me from barrreport. You have read my posts there and here. I don't think you can assume that I take the hobby as something that requires little thought or effort!!! I don't discourage people from asking how or why. I promote people to learn the hobby and be interested in the techy aspects of the hobby if they so wish. All I am adding to the above is that there are many many people who try to apply rigid rules to the hobby much as they may do with their science/mathemetics. It can work but more often than not it doesn't. Take the goverment scientists who state quite clearly that excess nutrients CAUSE/INDUCE the algae in the waterways? Is this true? They are the highly paid top notch scientists. In this hobby we know it isn't true at all and that it is fact the obsession with removing all plants and silt from the waterways that causes the algae.

Science even when done in the best laboratories by the best scientists can be way off the mark!!

I am not anti-intellectual in the slightest. I may have the lowest qualification/schooling level on this forum in that I left school at 16, I did not do any further education, I have no trade, I did not do chemistry nor had any interest in it. However I would do an IQ test with confidence that I would be in the top 10% of people!!!

Maybe my lack of schooling gives me the advantage of not already having the rigidity of what is taught. Maybe this leaves me to be more open minded than most. However if I push possibilities then scientists, chemists, mathematicians and even electricians tell me I cannot be correct. After all I am the uneducated one so I must be in the wrong 

One thing is for sure though. while they tell me I am wrong, I am the one telling them how they can sort their problems while I have none. I am the one who tells them where they have gone wrong. Many still don't listen and many others belittle anything that I say that doesn't conform with the 'already known facts'. There are enough people who are happy and some overjoyed with the results from the advice I have given for me to be happy though whether others believe me or not. lol

And no I am not Tom Barr, I have no research facilities, I have not finances nor room to enable testing to the levels that others may be able to. However I can use my own tanks to test things and I can read just like others on the internet and filter good information through the swathes of misinformation.

AC


----------



## Izzy

Philosophos said:


> Dave, 10,000K/6700K is exactly what I'm using right now. At 3wpg, I'm still finding it rather crisp and intense. Maybe I should take a look at straight 10,000k.
> 
> Color shift and drop in PAR isn't so bad, so long as you change the bulbs regularly. One thing most people don't realize is that most electronic timers will burn out CF faster. I've seen warnings on the osram/sylvania website about it.
> 
> -Philosophos


I have two types of timers. One is a digital coralife and the rest are the dials that spin mechanically.
Are both of these considered "electronic". I haven't checked all the links, but i'm trying to find the info on sylvania via google. What do they consider premature - one month less on twelve month life a CF?


----------



## Supercoley1

The mechanical ones are fine. More than likely the digital one will also be fine but some digital ones aren't.

I have all of my flouros on mechanical and the LEDS on a mixture of digital and mechanica (what I had to hand. lol)

This article that talks about them but not in too much depth. lol
http://home-owner-tips.suite101.com/article.cfm/digital_versus_analog_electrical_timer_switches

This one goes a bit further into the problem:
http://energystar.custhelp.com/cgi-...std_adp.php?p_faqid=3378&p_created=1193408235

On the theme of T8 this. lol. sometimes the more advanced item is not necessarily better :lol:

AC


----------



## Philosophos

Supercoley1 said:


> It is not that knowing PAR at source is less accurate than WPG. It is that you stop there and then estimate variables from there on which makes it a little pointless. Both mathematical/scientific Calculations will be way off the actual due to the unlimited amount of variables, many known and many unknown/ignored, and therefore you may as well just use the WPG without wasting so much time to get an inaccurate answer. Par at target(s)...very worthwhile if you have the facility. You are now looking at an actual accurate result with no need to estimate anything.


But this isn't the case. We've had to use PAR meters to figure out alterations for the WPG rule just recently because of the new reflectors on T-5 lighting, and their distribution because of going back to using multiple strips. The hobby already finds its self using PAR at source to adjust rules for people who don't want to figure this sort of thing out.



Supercoley1 said:


> I do not try to suggest that they are failing to understand science at all. Many of the people who fail understand the science but try to apply science to the question too rigidly. They already have the knowledge of 'What is correct'. Where they fail is that they then try to use mathematics and science but have the 'already known' factor already ingrained and then use this combination to get the answer on something with the amount of variables within a planted tank often means that the final calculation is way off the mark. If they were to start with a clean sheet and say to themselves 'everything I understand to be correct or proven may well actually be wrong. I shall ignore what I already understand to be right and assume nothing' then they would be more likely to be able to apply their findings to get the correct answer. While they apply previously understood knowledge to their results then their conclusions may have been swayed.


For every issue you can bring up with misunderstanding, I can name a logical fallacy. I think this is an issue that is best brought to the education system, and society as a whole. Most of it goes back to variations on argumentum ad verecundium. Humanity as a whole loves its infallible bastions of truth enough to ignore reality more often than I find tasteful.

I don't think we need to start with a clean sheet every time. I do think everyone needs to progress towards a point of knowledge where some sort of valuable exchange can happen. You're not teaching someone properly if the case will always be, "Me who does the teaching" and "You who does the learning." Peer review fixes this.

What I mean here is that observation is a good thing. Testing is a good thing if done with kits/equipment that is known to be accurate. The key is applying the results and coming up with the correct answer. I would suggest 99% of people who use the testing method and then apply those results to their tank from 'knowledge' gleaned from scientific research or even knowledgeable sources like forums can assume the incorrect variable and then are on the 'goose chase' rather than correcting the actual problem.



Supercoley1 said:


> EI is called lazy man's dosing BUT many of us are not lazy. We use the EI because we are not scared of higher dosing while many (including government scientists still say excess nutrients CAUSE/INDUCE algae. Many people still harp on about Ph crashes caused by CO2!!! We know that many times higher dosing than we do with EI is safe and we know that dosing excess does not cause (or induce as you state) algae. It will feed it but another variable within the tank will have induced it. We also know that PH crash is a theory and that what they really mean is KH crash. We then know that CO2 does not alter KH.


But EI is lazy; it guesses from dosing at a hypothetical in vitro vs measuring an active in situ. We hope we have reached certain numbers, but do not have full understanding of the system. Right now, it looks like a mess measuring in situ, but doing it allows us progress towards formulaic elegance. Dry weight analysis, column testing, etc. allowed EI to happen. Continuing the same allows for a further development of knowledge to understand variations within EI its self.

EI is a consumers method. This is what it is intended to be. Thankfully, it demands more understanding of ferts than ADA dosing methods. It creates better hobbyists. It still isn't the end though, and it's still lazier than what we could be doing.



Supercoley1 said:


> I agree but many do understand the correlations between all the parts and can make incorrect assumptions whilst still being much more knowledgable on science / maths than I


That's just specific knowledge of a system then. Saying that they'll understand just because they have a certain job or education in a similar field does not mean that they will have full understanding of your specific scenario. Again, back to argumentum ad verecundium.



Supercoley1 said:


> Exactly which nutrient INDUCES algae? Can't be any of the ones I dose!!! I have no algae in either my hi tec tank (LED lighting, CO2 injected with EI and heavy water changes) nor my non CO2 tank (LED lighting with minimal ferts and no water changes!!!)


Now we both know what I'm talking about here. It's the ratios of course. Different nutrient limitations cause different algaes.



Supercoley1 said:


> Thats one hell of an assumption. When did someone else take the time to figure this out for me? I have been one of the people arguing for a long long time about spread and people try to hit me with Lumens statements, that T5HO/CF is a mile better due to intensity, that Amano uses very highlight and put the Finch family article link in when Amano himself admits he uses quite loe light and tests show ADA light units are much lower PAR than expected. It is I (although not alone) that have been saying that T8 is better due to the ability to improved spread/coverage by using more tubes and therefore limiting the 'hotspot/lowspot' problems that can be cause with intense lighting. You know this from the barrreport so I don't know where you think I used other people's advice


I don't think you invented T-8 lighting, I don't think you were the first one to put it on a fish tank, and I doubt if you created the terms PAR or Lumen. I think you may have examined it after, and come to your own conclusions. Technology stands on the shoulders (or corpses) of its forebears, and challenging their assumptions is part of getting there. My intent was to point out this concept, more than to comment on your own efforts.



Supercoley1 said:


> What I mean about knowing the PAR at source only being as good as WPG is that fine you know the exact output of the light on your system with your ballast and your reflector. If you stop there and then try and methemtically/scientifically calculate the variables then you are no better off than with the WPG.
> 
> However if you are testing PAR through the tank at different target areas you are on the ball and are way ahead of the WPG/PAR at source knowledge. It's fine to know how much light you have over the tank but as you stop there and don't know where the light is distributing, where it is hitting etc and how much is being 'received' then you may as well just put the lights on top, move them about until everything grows well or alternatively use more tubes and spread them out to ensure that you get a closer to equal coverage  I am not pooh poohing science nor mathematics. I am just saying that if we are to test things we need to test the right things. If we want to know how our lights are performing then we need to test the area that we are using them for and not just taking the output.


If you don't know whether a light puts off 100 or 125 mmol PAR at the source, then how is it possibly more accurate to make further assumptions later? You can estimate, but knowing the difference between a 100 and 125mmol PAR light can be used as comparisons within these observations. One could hypothetically upgrade to a higher wattage light based on WPG and end up with a lower PAR rating, or less output than they counted on. Again, it comes back to examining a basic conjunction fallacy.



Supercoley1 said:


> In the UK we don't have a reliance/compliance with one form of lighting. We pretty much understand light (without PAR meter testing) and compared to the US we tend to use much less light. We tend to focus more on flow and CO2.


Which is the way the hobby should be heading. High light is something to reserve for aesthetics, commercial growth and learning IMO. I run high light on one tank because it forces me to improve my methods beyond what is required.



Supercoley1 said:


> Again you know me from barrreport. You have read my posts there and here. I don't think you can assume that I take the hobby as something that requires little thought or effort!!! I don't discourage people from asking how or why. I promote people to learn the hobby and be interested in the techy aspects of the hobby if they so wish. All I am adding to the above is that there are many many people who try to apply rigid rules to the hobby much as they may do with their science/mathemetics. It can work but more often than not it doesn't. Take the goverment scientists who state quite clearly that excess nutrients CAUSE/INDUCE the algae in the waterways? Is this true? They are the highly paid top notch scientists. In this hobby we know it isn't true at all and that it is fact the obsession with removing all plants and silt from the waterways that causes the algae.


You're attributing the issues of hobbyists leaning on theories rather than challenging them while advocating the WPG rule. Meanwhile you're saying that individual groups of scientists or positions of authority create the full body of knowledge. I'll say it again, this comes under argumentum ad verecundium. Validity within scientific methodology is not measured by your employer or education.



Supercoley1 said:


> Science even when done in the best laboratories by the best scientists can be way off the mark!!


Would you care to preface that with some qualifiers? "Some people in some rooms might be wearing a cat on their head." I guess a picture of a cat on your head is fine too.



Supercoley1 said:


> I am not anti-intellectual in the slightest. I may have the lowest qualification/schooling level on this forum in that I left school at 16, I did not do any further education, I have no trade, I did not do chemistry nor had any interest in it. However I would do an IQ test with confidence that I would be in the top 10% of people!!!


Wow, it's like reading my own background story. Anyhow, I wasn't saying that you're anti-intellectual, or that it's your policy to encourage it. But, in this case, I find encouraging not knowing because it's easy to fit under that category.



Supercoley1 said:


> Maybe my lack of schooling gives me the advantage of not already having the rigidity of what is taught. Maybe this leaves me to be more open minded than most. However if I push possibilities then scientists, chemists, mathematicians and even electricians tell me I cannot be correct. After all I am the uneducated one so I must be in the wrong


Also having a severe lack of education, I find that people who have been through schools have passed tests of test taking abilities. They have an understanding for the application for which they have been taught, and often the expectation that this will lead to success. I won't deny that it can do this, but it can also lead to mediocrity. It is the ability to absorb a large body of knowledge without losing the ability to cross-apply general principles that I see as valuable.



Supercoley1 said:


> One thing is for sure though. while they tell me I am wrong, I am the one telling them how they can sort their problems while I have none. I am the one who tells them where they have gone wrong. Many still don't listen and many others belittle anything that I say that doesn't conform with the 'already known facts'. There are enough people who are happy and some overjoyed with the results from the advice I have given for me to be happy though whether others believe me or not. lol


And this is where being a piss poor human being is the result of humans who don't understand them selves. People do the same sort of thing when you give them any point of confidence, and then introduce them to an unfamiliar situation. I've seen the same pattern most noticeably in martial arts. Defence mechanisms are lovely.

-Philosophos

*edit* This has been one of the most enjoyable debates I've had on a forum in a while. I think we've probably lost our audience though >.<


----------



## Supercoley1

I am quite enjoying the debate too and I think others are probably chuckling at things. lol

I don't mean someone does the teaching and another does the learning. I think the teacher can also learn off the pupil  What I mean is that many people have their pre 'taught' understanding and are then pre-biased when applying results to theorys. By clean sheet I mean going into everything with an open mind and being open to the fact that the 'pre taught FACT' may in fact be incorrect before assuming the conclusion.

I don't think you can say it is easy. After all dry weight analysis is not something that 99% of people have the facility to do let alone interest

I think by using EI we know we are adding more, we don't care about exact measure, we are not scared of the 'nitrate toxicity scaremongering' etc. If we were to be trying to add 'the rght amount' we would be testing day by day with plant growth and never be adding the same. One day X amount the next day X+1 amount, prune and test, X-2 amount. I don't think that is anyone's aim!!!

I have used lean dosing as well as EI. I do EI these days because I do heavy water changes anyway and can't see the point in continual testing to use leaner methods. Maybe I am lazy for not testing and weighing every day  Everything we do in all areas of life are lazier than 'we could be doing.' lol

What I mean is that people in certain fields have an understanding of an area and if that are happens to be chemistry, physics, biology etc they transfer their understandings to this hobby. They then refuse to believe anything different to the hundred text books they learnt from and baffle people like me with scientific equations rather than talk straight. They try to explain why they are right rather than challenging why their 'understanding' isn't working in their setup. they also cannot answer why if their understanding is correct and my method contradicts their understanding why I have success. They go on to hide behind their symbols and equations which leads me to the usual 'My tank looks better than your. lol'



> Now we both know what I'm talking about here. It's the ratios of course. Different nutrient limitations cause different algaes.


Different LIMITATIONS. Aaah I get you now. I didn't see the word limitation previously. Goes without saying limiting anything will lead to a problem somewhere. Tell that to the government scientists who blame excess rather than defficiency.

No i didn't invent anything  I used the light just as everyone else did that was available. however I moved up and then back down. I 'downgraded' while others belittled any suggestion that T8 could be better than 'more advance technology' T5HO is king and cannot be beaten. Hmmmm

The same is now happening where people are refusing to believe in LED. The MH lovers are saying 'Not as many Lumens', 'Not as good as MH' the tests show that less lumens but more PAR. Their corals weren't dying they were bleaching!! Again Lumens is thrown in here. Often by people with much more knowledge than me. It looks brighter so it must be more light???? We know different.



> If you don't know whether a light puts off 100 or 125 mmol PAR at the source, then how is it possibly more accurate to make further assumptions later? You can estimate, but knowing the difference between a 100 and 125mmol PAR light can be used as comparisons within these observations. One could hypothetically upgrade to a higher wattage light based on WPG and end up with a lower PAR rating, or less output than they counted on. Again, it comes back to examining a basic conjunction fallacy.


I am not saying it is a useless measurement. I am just saying why bother testing the PAR of a light at source and stopping there. If you have the equipment to measure at source then measure at target instead. If we are just saying that we can create a database where people can look at their lamp model etc and see a PAR measurement to compare then this database needs to include every ballast available, every reflector available and other variables so that someone can enter all the variables and see a number.

Why do this when you can see 18W printed on a box. divide it by 10USG which you know and then say 'should be enough. Lets see'. Will someone seeing Ahh 150mmol at source mean they know any different? They will still be saying 150mmol/10USG. Ahh excellent...'should be enough, Let's see' :lol:

I would suggest my 1.12WPG of high power LED is actually medium to highlight!!! Don't tell anyone else or I will be shouted down with Lumens speak. lol. I have no problems other than plants grow too fast.



> You're attributing the issues of hobbyists leaning on theories rather than challenging them while advocating the WPG rule. Meanwhile you're saying that individual groups of scientists or positions of authority create the full body of knowledge. I'll say it again, this comes under argumentum ad verecundium. Validity within scientific methodology is not measured by your employer or education.


No I am saying that hobbyists follow what they are told until they learn better. Scientists more often than not will not veer from what they 'know' whether right or wrong. Many of them see science as a progression only and will not consider that maybe some things were wrong from the start and the progression is already more incorrect at which point they should disregard their previous understanding. They still have that 'knowledge' but now they can start at the beginning and test the theory rather than progressing on from the last 'understanding'.



> Would you care to preface that with some qualifiers? "Some people in some rooms might be wearing a cat on their head." I guess a picture of a cat on your head is fine too.


I mean as the above statements. Government scientists and research laboratories and environment agencys - Top qualifications - Top laboratories - Top equipment and facilities = Excess nutrients are causing the algae in our waterways. It isn't that we are emptying the plant growth out of them. This is one example.

Another is this week = Take Aspirin every day it is good for you. Next week Don't take aspirin every day it is bad for you.

This week = Drink X amount of water daily. Must be water not juice or coffee etc. Pure water. Next week It can be any liquid as it derives from water anyway.

Where do these statements come from? Top goverment scientists with top facilities. I for one don't take any medicines unless it is prescribed. No paracetamol, No Aspirin. I drink zero water. I drink a few cups of coffee a day and nothing else. I am as healthy as and ride my road bike for miles and miles (then have a coffee when I get home) I never need to go to the doctor, am rarely ill, and have more energy than most people.

How is it possible. It cannot happen. The studies say I should be pretty sick, unhealthy etc.

Answers on a postcard please :lol:



> Wow, it's like reading my own background story. Anyhow, I wasn't saying that you're anti-intellectual, or that it's your policy to encourage it. But, in this case, I find encouraging not knowing because it's easy to fit under that category.


I'm glad to have met some as stupid as me :lol:



> Also having a severe lack of education, I find that people who have been through schools have passed tests of test taking abilities. They have an understanding for the application for which they have been taught, and often the expectation that this will lead to success. I won't deny that it can do this, but it can also lead to mediocrity. It is the ability to absorb a large body of knowledge without losing the ability to cross-apply general principles that I see as valuable.


Indeed, I was a pretty rebellious teenager and missed a lot of school from 11-14. I should've been well behind yet I graduated with 11 (standard 16 year old exams inthe UK) GCSE at C or above. The national average is 5!!! I got better results than many who go onto further education (which I didn't) and how? Anyone can read books and replicate their research onto test papers. Memory is not knowledge. Tests are test of memory more often than not which is why coursework is brought into the curriculum more and more so that it isn't a simple memory test. Thankfully I saw sense before all was lost and gave myself 2 years to catch up the 3 lost years + final 2 years (5 years learning in 2 years) and beat many of my fellows. lol. I was actually one of only 2 people in my county in my year that got 100% in the basic numeracy Exams. By basic it wasn't 10 x 2 = . :lol: it meant no calculator which seem to have flummoxed all but one other of thousands of 16 year olds in that year. lol

So the answer is oyu don't need to brains of britain to pass tests. A good memory is all that is needed. You also don't need to be brains of britain to understand many of the aspects of this hobby in depth but it does help to have an open mind, understand some basic science, be able to correlate what you see and what you test and apply their findings to a conclusion as well as question any tes / observation that contradict each other etc.



> And this is where being a piss poor human being is the result of humans who don't understand them selves. People do the same sort of thing when you give them any point of confidence, and then introduce them to an unfamiliar situation. I've seen the same pattern most noticeably in martial arts. Defence mechanisms are lovely.


Indeed. I have posted help for some people who are overjoyed at the result of just being able to grow healthy plants in their aquarium. Their tank looks a mess to me but the plants are healthy and they are happy and that makes me feel good. The ones that argue without reason I leave to fester in their algae nightmare. The good thing about this hobby and forums is that there are thousands like us that can give differing opinions, different methods, different points of view and the user can benefit (as well as sometimes suffer) from the knowledge, experience of others. Can get confusing when several disagree with each other but at least it has moved on from buying a book detailing the rules that were decided to be FACT in 1752 and have not advanced since. lol

PAR v WPG? PAR is far superior than WPG. I just don't see the point in having a figure (125Mmol/18WPG) and then still having to work in variables. It is still a rough guide and still more than likely as confusing as knowing which tubes, how many, whic K, which diameter etc. lol

I would love a PAR meter to borrow for the day to test my setup but alas we in the UK don't care too much for the exactness of this. We want to know the system, we want to understand the methods. We don't particularly care whether it measure low, medium or high as long as it works. We do however want to measure CO2. Several of us (including myself) believe in high/low CO2 plants and not high/low light plants so our focus is on the CO2 where the US would be on the light. For the same reason we focus on a different aspect.

AC


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## Philosophos

Supercoley1 said:


> I don't mean someone does the teaching and another does the learning. I think the teacher can also learn off the pupil  What I mean is that many people have their pre 'taught' understanding and are then pre-biased when applying results to theorys. By clean sheet I mean going into everything with an open mind and being open to the fact that the 'pre taught FACT' may in fact be incorrect before assuming the conclusion.


I agree then. People do it far too often. They weren't paying attention when told to question everything.



Supercoley1 said:


> I think by using EI we know we are adding more, we don't care about exact measure, we are not scared of the 'nitrate toxicity scaremongering' etc. If we were to be trying to add 'the rght amount' we would be testing day by day with plant growth and never be adding the same. One day X amount the next day X+1 amount, prune and test, X-2 amount. I don't think that is anyone's aim!!!


But that's already what large commercial hydroponics systems do. They recycle the water and re-top the nutrients. It's cheaper in bulk. Cheaper for them should mean cheaper for the consumer.

Besides that, understanding what nutrients are dosed and why through observing uptake makes for better balanced ferts. Right now we dose broadly. It would be nice if there were enough dry weight analysis to custom dose for the needs of an individual tank. Iron comes to mind foremost for this one.



Supercoley1 said:


> I have used lean dosing as well as EI. I do EI these days because I do heavy water changes anyway and can't see the point in continual testing to use leaner methods. Maybe I am lazy for not testing and weighing every day  Everything we do in all areas of life are lazier than 'we could be doing.' lol


True enough, but I still like to push my self when possible- sometimes it really pays off. Not everyone can have a lab, but taking the initiative to do their own small part sure helps.



Supercoley1 said:


> What I mean is that people in certain fields have an understanding of an area and if that are happens to be chemistry, physics, biology etc they transfer their understandings to this hobby. They then refuse to believe anything different to the hundred text books they learnt from and baffle people like me with scientific equations rather than talk straight. They try to explain why they are right rather than challenging why their 'understanding' isn't working in their setup. they also cannot answer why if their understanding is correct and my method contradicts their understanding why I have success. They go on to hide behind their symbols and equations which leads me to the usual 'My tank looks better than your. lol'


Ya, that's about it sometimes. In my experience, it's often more of the inverse that happens. I get people requesting that I do 100% of the work on their fert methods and tank set-up often enough. If I do, they never know why it works, and their tank turns to goo. Guess who catches the blame? I try to make people want to learn, and help them along the way.



Supercoley1 said:


> Different LIMITATIONS. Aaah I get you now. I didn't see the word limitation previously. Goes without saying limiting anything will lead to a problem somewhere. Tell that to the government scientists who blame excess rather than defficiency.


I have. They don't care. They don't want to know. Try explaining an about-face like that to your higher ups all the way along the chain.



Supercoley1 said:


> No i didn't invent anything  I used the light just as everyone else did that was available. however I moved up and then back down. I 'downgraded' while others belittled any suggestion that T8 could be better than 'more advance technology' T5HO is king and cannot be beaten. Hmmmm


T5HO has longer lasting bulbs, that's my attraction. Still an expensive initial investment.



Supercoley1 said:


> The same is now happening where people are refusing to believe in LED. The MH lovers are saying 'Not as many Lumens', 'Not as good as MH' the tests show that less lumens but more PAR. Their corals weren't dying they were bleaching!! Again Lumens is thrown in here. Often by people with much more knowledge than me. It looks brighter so it must be more light???? We know different.


Then they need to be informed of the difference. Clearly their knowledge of science isn't so hot as they like to think in that specific area.



Supercoley1 said:


> I am not saying it is a useless measurement. I am just saying why bother testing the PAR of a light at source and stopping there. If you have the equipment to measure at source then measure at target instead. If we are just saying that we can create a database where people can look at their lamp model etc and see a PAR measurement to compare then this database needs to include every ballast available, every reflector available and other variables so that someone can enter all the variables and see a number.


Naturally it wouldn't be useful if you had the equipment. On the other hand, if companies started printing the micromoles PAR on their light, it'd make it superior to WPG. Failing that, publishing an article regularly with listings of PAR for popular brands would definitely be helpful.



Supercoley1 said:


> Why do this when you can see 18W printed on a box. divide it by 10USG which you know and then say 'should be enough. Lets see'. Will someone seeing Ahh 150mmol at source mean they know any different? They will still be saying 150mmol/10USG. Ahh excellent...'should be enough, Let's see' :lol:


Better 150mmol than "what may be 100 or 150mmol, I'm not sure" - it refines the measurement. Yes, there'd still be the wait and see, but at least one step of confusion would be removed. Buying a new bulb wouldn't leave people wondering if they were really getting more PAR, or just a higher wattage bulb. Brand comparisons would be far easier; it'd actually save people money.



Supercoley1 said:


> I would suggest my 1.12WPG of high power LED is actually medium to highlight!!! Don't tell anyone else or I will be shouted down with Lumens speak. lol. I have no problems other than plants grow too fast.


1.12wpg? Probably mid to high. My brief reading on the subject always made me think it's about double most CF.



Supercoley1 said:


> No I am saying that hobbyists follow what they are told until they learn better. Scientists more often than not will not veer from what they 'know' whether right or wrong. Many of them see science as a progression only and will not consider that maybe some things were wrong from the start and the progression is already more incorrect at which point they should disregard their previous understanding. They still have that 'knowledge' but now they can start at the beginning and test the theory rather than progressing on from the last 'understanding'.


In that case they're mistaking science for religion. I'll leave it at that.



Supercoley1 said:


> I mean as the above statements. Government scientists and research laboratories and environment agencys - Top qualifications - Top laboratories - Top equipment and facilities = Excess nutrients are causing the algae in our waterways. It isn't that we are emptying the plant growth out of them. This is one example.


I don't even want to touch the bias in that one. This is the same reason I stay out of global warming debates, and never watch televised election debates. It's inevitably full of fallacies in an inductive search for short term greed.



Supercoley1 said:


> Where do these statements come from? Top goverment scientists with top facilities. I for one don't take any medicines unless it is prescribed. No paracetamol, No Aspirin. I drink zero water. I drink a few cups of coffee a day and nothing else. I am as healthy as and ride my road bike for miles and miles (then have a coffee when I get home) I never need to go to the doctor, am rarely ill, and have more energy than most people.
> 
> How is it possible. It cannot happen. The studies say I should be pretty sick, unhealthy etc.
> 
> Answers on a postcard please :lol:


There's more sources of water than just pure water. If you're sucking back things that are 90% moisture, you're probably still getting it. You may be living dehydrated as well.

I also get rather skeptical around the UK health care system. This is the government that's allowed homeopathy to have a place along side real medicine. Not everyone with a PhD is looking out for the rest of the world.



Supercoley1 said:


> Indeed. I have posted help for some people who are overjoyed at the result of just being able to grow healthy plants in their aquarium. Their tank looks a mess to me but the plants are healthy and they are happy and that makes me feel good. The ones that argue without reason I leave to fester in their algae nightmare. The good thing about this hobby and forums is that there are thousands like us that can give differing opinions, different methods, different points of view and the user can benefit (as well as sometimes suffer) from the knowledge, experience of others. Can get confusing when several disagree with each other but at least it has moved on from buying a book detailing the rules that were decided to be FACT in 1752 and have not advanced since. lol


I tend to direct people to read from good sources. I don't support forum use from random individuals for the new aquarist. The mangling of ideas that happens on any forum is pretty bad. After they know what's out there, then it's worth coming here for help with individual issues.



Supercoley1 said:


> PAR v WPG? PAR is far superior than WPG. I just don't see the point in having a figure (125Mmol/18WPG) and then still having to work in variables. It is still a rough guide and still more than likely as confusing as knowing which tubes, how many, whic K, which diameter etc. lol


125mmol par = 18wpg? I'm a little confused here. mmol par is a measurement at a point for how much light is exerted as far as I understand. 125mmol at source could be had from a 24w bulb or a 150w bulb at the source, depending on efficiency. The difference would be the length of the light and the size of the tank for WPG.



Supercoley1 said:


> I would love a PAR meter to borrow for the day to test my setup but alas we in the UK don't care too much for the exactness of this. We want to know the system, we want to understand the methods. We don't particularly care whether it measure low, medium or high as long as it works. We do however want to measure CO2. Several of us (including myself) believe in high/low CO2 plants and not high/low light plants so our focus is on the CO2 where the US would be on the light. For the same reason we focus on a different aspect.


For the average aquarist, 1.5-2.5 wpg of light will just about always work, I agree. For people pushing things farther, or reducing their power bill by skimming the low end, I could see it being valuable. Hell I even find my self toying with lumens and mmol par to see how bright looking a tank can get without increasing growth demands.

-Philosophos


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## Supercoley1

Something went wrong there. You virtually agreed with the whole post. lol

BUT.............:lol:

The government stances on the fertilisers pleases the greenies who want organic. Therefore I guess they supress other suggestions. It also means they please the non greenies who want pretty grassbanked waterways too. Many more reasons I'm sure.

I agree with you r.e. the 'climate change' debate. Far too many greenies moaning about wasting electricity yet they are definately running a fish tank or tanks and a PC whilst complaining. lol



> T5HO has longer lasting bulbs, that's my attraction. Still an expensive initial investment.


Are you sure it is the tubes or the ballasts they use??? T5HO runs on programmed electronic ballasts which prolong bulb life. Guess which ballasts I run my 2 year old T8s off???  Oh and they are on mechanical timers not digital ones :lol:

I would suggest T8 and T5 last longer than T5HO because the T5HO has to be forced a lot harder to achieve the HO. They are 'sort of' overdriven.



> 1.12wpg? Probably mid to high. My brief reading on the subject always made me think it's about double most CF.


More than likely. I am not a fan of CF really. limits your options by having huge amount of light confined to a small area. I think linears will always be better than CF/PL wether it be T8, T5 or T5HO.

I've been watching televised election debates for the last week. lol. I love listening to the spin. I love the banter between the parties. Politics is one of my favourite watches  Short term greed. Are you sure you haven't been watching the same UK politics as we have :lol: It is long term greed over here though 

Maybe I am living dehydrated. I don't eat fruit but I do eat a lot of veg so I guess thats some water. I have the occasional soft drink here and there and a nice glass of port if I'm feeling particularly chuffed with myself.

UK health system and homeopathy??? I think they have to facilitate the option as oyu would expect from a democratic society but it is never suggested in the hospitals/Doctors. I think its more a case of if they are asked about it then they give the info and facilitate rather than give the option of which treatment you want. Then how would I know. Haven't seen a doctor for 10 years 

I tend to use the sites I trust. Ones where several sources will give advice that compliments the others. Also where any assumptions that are wrong are corrected by the same people. However this can also mean that we are group bullying our point of view to the OP. Maybe that is wrong but then better to have one group all say the same thing than 15 different contradictions.



> 125mmol par = 18wpg?


I was meaning 18WPG as a simple measurement. It could have been X Mmol/X WPG. Yes a PAR is from the area the tube(s) the meter is under 

AC


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## Dryn

I feel hijacked. Should've made the title "to be scientific or not to be..."


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## Philosophos

Supercoley1 said:


> Something went wrong there. You virtually agreed with the whole post. lol


Nah, that just means we're communicating in an effective way. I think our only real issue is working out PAR @ source vs. WPG.



Supercoley1 said:


> Are you sure it is the tubes or the ballasts they use??? T5HO runs on programmed electronic ballasts which prolong bulb life. Guess which ballasts I run my 2 year old T8s off???  Oh and they are on mechanical timers not digital ones :lol:
> 
> I would suggest T8 and T5 last longer than T5HO because the T5HO has to be forced a lot harder to achieve the HO. They are 'sort of' overdriven.


Definitely the ballasts, but if you've got the ballast why not do a thinner bulb to reduce restrike? T5HO does double CF anyhow from what I've read; 1x a year replacement sure beats 6 months.



Supercoley1 said:


> More than likely. I am not a fan of CF really. limits your options by having huge amount of light confined to a small area. I think linears will always be better than CF/PL wether it be T8, T5 or T5HO.


CF is cheaper in the short term, so there's an attraction. I use a higher wattage and elevate for better spread.



Supercoley1 said:


> UK health system and homeopathy??? I think they have to facilitate the option as oyu would expect from a democratic society but it is never suggested in the hospitals/Doctors. I think its more a case of if they are asked about it then they give the info and facilitate rather than give the option of which treatment you want. Then how would I know. Haven't seen a doctor for 10 years


Facilitating the option and even covering homeopathy through any method other than self-pay kind of seems ridiculous to me. I don't think it should get that support until it can pass some sort of medical standards test. Better than placebo would be a good start.



Supercoley1 said:


> I tend to use the sites I trust. Ones where several sources will give advice that compliments the others. Also where any assumptions that are wrong are corrected by the same people. However this can also mean that we are group bullying our point of view to the OP. Maybe that is wrong but then better to have one group all say the same thing than 15 different contradictions.


I've never cared who said it, so much as how much sense it makes, and what the results are. Anyone afraid to contradict a group because of how many support it clearly isn't thinking for them selves, and they're putting social convenience before searching for the truth.

Sorry about the hijacking, Dryn. If I get a decent block of time I'll do some topic-related research and post my opinion on it.

-Philosophos


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## Supercoley1

Yep apologies. We are kind aon the same topic although drifting away and back again. lol

I would've said PAR v WPG was a scientific orientated question anyway 

I use T8 because they are cheap, easy to get hold of and lets me use more spread 

I have read articles that suggest T5HO loses only 5% or so after 8000 hours. I never change d my T5HO or T8s under 2 years when I ran them.

AC


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## Dryn

Not changing for two years? I guess it just goes to show, plants are very adaptable. I'd be willing to bet trimming wasn't as needed in that last years as it was the year before.


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## Supercoley1

Its just like the WPG rule is incorrectly applied to modern lighting when it in fact is meant for T12.

People apply the 'change your tubes 6 monthly or yearly' to modern tubes. It is more than likely true for lights than run off magnetic ballasts but T5HO does not run off magnetic ballasts.

T5HO runs off either programmed or instant start electronic ballasts (more than likely you have a programmed start.)

This is quite a good article where it states in a test that both T5HO on programmed ballast and T8 on Instant Start ballast held 95% of their original lumens after 40% of the lamp life (These lamp lifes are obviously until it stops working so the life could mean it is barely lit at the end of it's life. Whether the Lumens are retained but PAR goes down I cannot answer but I would doubt it.

http://www.aboutlightingcontrols.org/education/papers/Copy of high-low-bay.shtml

I didn't notice any difference in growth at 2 years old. Was still having to hack away at 'slow growers' just like I did when they were new 

It is still running now at 3 years old over an emersed setup. No idea on the Lumens or PAR but it works so I leave it there 

The T8s are also running on programmed electronic ballasts and the tubes and ballasts were bought in December 06. They are still doing well over emersed setups.

This is one of those questions that really could be investigated to see whether it is one of the old school realities that has become an obsolete problem with the development of technology.

Older tanks with T8s in will more than likely have magnetic ballasts in them. Not sure about more modern tanks with T8s manufactured in the last few years. My Fluval that has LEDs over it now originally had a magnetic ballast powering the T8s until I swapped it out for the electronic ones.

Easy to see. Magnetic ballasts use the small round tubular starters.

Harder to see if you have an 'instant start' or a 'delayed/programmed start' ballast. Often not printed on the ballast housing. T5HO will definately be using electronic but which one? Tubes on instant start will still last longer than magnetic but not as long as programmed start.

How long for each ????? Needs to be tested properly. lol

Its a question of weighing up. The average user is just going to get T5HO but (using nasty Lumens  ) T5HO provides less Lumens per watt than T8. It provides more W per inch though. T5 provides the most Lumens per watt but when overdriving to be T5HO it loses a little.

Therefore if space is an issue T5HO is the one. If space is not an issue then T8 or T5 standard are the best. Means more tubes but will provide more lumens per W and therefore should be more efficient than T5HO.

Then take into consideration the peak ambient temperatures the 2 tubes are designed to work at. T5 and T5HO is 35ºC and T8 is 26ºC. Is your house's ambient temperature 35ºC??? Therefore are you getting the peak output?

AC


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## BryceM

Just to play devil's advocate here.......

One of the supposed benefits of T5s is optomized reflector design. Most people who use T5s use highly conformal reflectors - often each tube has its own. This effectively makes them far more efficient than the average T8/reflector combo. This alone could account for the large volume of "holy cow T5s are great!" posts on all sorts of forums.


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## ingg

BryceM said:


> Just to play devil's advocate here.......
> 
> One of the supposed benefits of T5s is optomized reflector design. Most people who use T5s use highly conformal reflectors - often each tube has its own. This effectively makes them far more efficient than the average T8/reflector combo. This alone could account for the large volume of "holy cow T5s are great!" posts on all sorts of forums.


Ayep.

Start running models of reflectors for T8's and T12's for optimal reflectors, and you get awfully wide awfully fast (Hint, you should be coming out at about 4" minimum per T8 bulb, and 6" per T12 bulb). T5's can get it done in a realistic amount of space, especially when using T5HO's (and I strongly suspect the "real" reason that T5HO overtook T5NO was getting enough output over a small enough space, surprise! ).

Same goes for CFL's, honestly, since they are bent back on themselves they aren't all that much more efficient (in terms of reflector design capable) than T12's - just the bulbs are a lot more powerful themselves as a starting point. As good as AHSupply reflectors are for CFL, they don't hold a candle to the output of a higher end T5HO fixture - it's all about the reflectors!

For the OP, I would say there is a wide range of coefficients to be used for reflectors in your modelling (for both bulb style and reflector quality/build style) and that adds a whole new level of complexities, but I really do like the idea!


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## Philosophos

Well it looks like this theory will get tested and refined in the end. I'm going to be getting a PAR meter in the next couple of months [smilie=b:

-Philosophos


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## mudboots

I'm giving this thread a bump because I've been trying to find this info for a while. Trying to figure out how many wpg I needed for two tanks on opposite ends of the spectrum (one is 20 gallons, one os 125 gallons) was bugging me, but the plants seemed to be doing fine. Seeing the PAR calculations, I realize that I have a lot more light than I thought in my 125. 1.25 wpg in this tank isn't so "Low Light" as I thought.


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## mudboots

I forgot to mention that I ran the calculations using the assumed variables on the 125 and 20, but also splitting the 125 in half to see what the difference was since it's 72 inches long. For the surface variable, instead of using .4 I used .3 because I have no filtration creating ripple, though I di have some surface film from time to time. Because I still have a lot of unanswered variables (such as the effect of tank length on light spread et cetera) I have no idea how valid or even interesting the following numbers are, but here they are anyway.

20 Gallon NPT (24"x12.5"x17") with 48 watts T5HO (2.5 wpg) - I came up with around 140 PAR at surface and 53 PAR at substrate.
125 Gallon NPT (72"x18"x22") with 156 watts T5HO (1.25 wpg) - I came up with around 458 PAR at surface and 172 PAR at substrate.
Using half the 125 with half the watts (one fixture) (1.25 wpg) - I came up with around 230 PAR at surface and 86 PAR at substrate.

Perhaps my figures are just way off. I'd be interested in looking more deeply into this, especially as it applies to aquariums of various lengths and depths. I was really surprised at the numbers from the 20 gallon because of the wpg guidance.


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## spstimie

thankfully my local reef club has a par meter. I have tested several 250watt hqi halide bulbs in different reflectors on different ballasts. All saltwater but I think it will kill the idea that there is an equasion that can tell you. My aquamedic 2x250 fixture on 75(18") gallon: with aquamedic 20k bulbs put out 250 at the surface and 70 at the sand, with coralife 10k bulbs 1100 at the surface and 750 at the sand, and with phoenix 14k bulbs 800 at the surface and 500 at the sand. These same phoenix bulbs the same hight over a 215(25 or 30" tall cant remember), in different reflectors, and on different ballasts put out 1000 at the surface and 700 on the sand. I am using a GE 6500k power compact bulb over my 3 gal plant tank so maybe I will borrow the par meter and see what that puts out. 

Oh yeah all those numbers were taken 6" off the water on small polyp stony coral tanks. They need lots of light. My 75 gallon has a 650watt fixture.


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