# WPG NO vs PC vs HO



## urville (Sep 20, 2004)

Okay.

What is the difference, reflectors aside. Lets say we had the same reflector for all three types of light. just to level the field.
I would need between 3 and 4 WPG NO lets say.
How many WPG is that from PC lighting??
Or T5 HO?

is there some formula or factor? i need half as much pc compact light?
or 2/3's as much HO light?

Ian


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## Simpte 27 (Jul 16, 2004)

Not really a formula but has to do with lumens. 3-4 wpg N.O. can be duplicated with 2-2.5 wpg pc or T5. N.O. and T5 have better spread than PC. PC penetrates better but unless you have a REALLY deep tank, its not really an issue.


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## urville (Sep 20, 2004)

but i can adjust spread with any buld with a different reflector right?
like i have a 29 ehich is 30x12x18.... it's only 16 to my substrate so in such a tank with only 12 front to back and 16 deep PC would be okay?

hehehe, maybe i am worrying too much, but you should see my lilaeopsis, and now i dont know how to fix them less to cut the tall leaves once smaller ones start coming in after i get a better light.

when most people on here say you need 3-4 WPG are they saying NO or PC and T5?


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## Simpte 27 (Jul 16, 2004)

Why ask the question if you don't want the answer?  You said all things being equal then you point out what you can adjust. I just gave the simple answers.

And yes you are worrying too much.


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## urville (Sep 20, 2004)

Ahhhh simpte... i asked all things being equal to see the exact answer. now i can think about things i can control. i now know that PC's the same light at around half the wattage. so now if spread sucks, i can change it

i know i know... but to hear some poeple it's like everything will die, or your lilaeopsis will never grow like your talking about without this, and only this. what? dont you have 1200 for lighting?
hehehe

i just want things like my glosso to not get tall.. it isnt tall but then i just planted it so...
Ian


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## shalu (Oct 1, 2004)

With the same reflector(but remember, bulb size does count for reflector efficiency! The smaller, the better; one bulb per reflector is better than multi-bulb reflector), the difference between NO, PC and T5 is small. Lumens per watt is typically 82-87 for 48" T8/T12 bulbs I used(2800 rated lumens from 32w T8, 3300 lumens from 40w T12), it is typically 85-95 for PC/T5 bulbs roughly.


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## urville (Sep 20, 2004)

So basically your saying the advantage of using PC's is only depth penetration and almost a nil factor of effciency?
So why do they cost more? I could just have the same thing in NO's and it's not any more efficient? well a sliver more....
thats hardly worth the money.

i dont get it, why does everyone tout them so much?
or rather which one of you is correct?


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## shalu (Oct 1, 2004)

The EFFICIENCY of the REFLECTOR makes the world of difference, and the size of the bulb contribute to that as well(PC/T5 is much smaller than T8/T12, and they are slightly more efficient in lumens/watt as well). I have been trying to get that across to you many times. If one uses crappy fixture/reflector(you don't know what a good one is until you see one, AHSupply), then it really does not matter if it has 4x55w pc bulbs in it or not, because a shop light with 220w will do a similar job. Without considering the efficiency of reflectors, ODNO can even provide more lumens/watt based on my measurements in PT thread.


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## urville (Sep 20, 2004)

you know what. i cant get the AH Supply site to let me order anything anyway. The ordering times out on me everytime. not that i could build that thing anyway. i'm gonna call and ask if i can buy their reflectors only, then it wont matter apparently what i buy.
right?


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## shalu (Oct 1, 2004)

Here is a pc to pc comparison:
http://ahsupply.com/Comparison.htm
There are PCs, then there are PCs. Talking about PCs without taking into account of reflectors is totally meaningless, let me say it again.

I have the numbers to back up my assertion that without considering reflectors, PC/HO T5 are only marginally better than NO bulb for the same watts, do you see any numbers to the contrary? There are many wild claims on the internet, depending on who you believe. Like people used to think 4x ODNO means using 4x the power.


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## urville (Sep 20, 2004)

okay... look i could build that reflector to that shape, and find similar material or buy reflectors from them okay. so now i have the greatest reflector ever, what bulb makes more light? can i use 65 watts pc in lieu of 120 NO?


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## shalu (Oct 1, 2004)

T5(they have special individual reflectors from retrofit kits usually, 2" wide each $22 or so) would be slightly better than PCs to maximize reflector efficiency. PC has the draw back of twin-bulb config, which slightlly reduces reflector efficiency, so I guess a T8 with same reflector has similar effect, but a bit lower lumen/watt. Apart from PCs, I use AHSupply on T12, T8, T6 and T5 bulbs on my tanks, ODNO or NO.

Then again, in my opinion, watt for watt, the reflector makes 80% of the difference, 20% due to the bulbs(half of it still related to reflector efficiency due to bulb size, another half related to lumens/watts efficiency). So basically you can use cheap T8 or PCs, both work.

The other issue is, you need a lot more NO bulbs for the same wattage of PCs. Configuration can be messy. Or you can do ODNO, for which you need to buy ballasts. More bulb, fewer watts/bulb means even coverage but not as high local intensity peaks as directly under PCs.


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## SnyperP (Dec 10, 2004)

You can't copy a reflector designed for a PC light and use it with t-8/12's. Their designed specifically for the bulb to enchant, or should i say minimize restrike onto the bulb.

You ask why people use PC or T-5 when their only slightly more efficent than other bulbs. The other factor is size. You can squeeze much more lighting together with proper reflectors in a space using T-5 than you could t-12. Same thing with pc in regards to t-8/t-12.


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## shalu (Oct 1, 2004)

SnyperP said:


> You can't copy a reflector designed for a PC light and use it with t-8/12's. Their designed specifically for the bulb to enchant, or should i say minimize restrike onto the bulb.


Yes, you can. A parabola is a parabola, the best efficiency is achieved for a POINT source(zero diameter in this case, actually) at its focus point/line. The PC reflector is still basically a parabola, but wider to ACCOMODATE the PC bulb. It does not mean it works less well for a single tube(smaller is still better). An example: AHSupply with T8 


And I agee, you can hardly pack enough NO bulbs with proper reflectors to achieve the intensity of PC. ODNO will work much better.


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## urville (Sep 20, 2004)

ok whoa
you said


shalu said:


> the difference between NO, PC and T5 is small.


but you also said


shalu said:


> you can hardly pack enough NO bulbs with proper reflectors to achieve the intensity of PC..


so whats the difference between Intensity and Lumens per watt? how does the two effect plant growth?

is 65 watts or even 55 if i have the proper reflector going to put me where i need to be? i'd like i guess to be around 3 to 3 and a half WPG, i should be able to grow red plants, foregrounds, and lilae, and most anything with that much WPG NO right? So what should i shoot for PC? I mean I just dont want to find a used 96watt and i'm really sitting over 4 WPG... like I found a used JEBO 36" 96watt PC fixture. with taking into account the reflector and all this other stuff and whatever big math your using to support it, where will i be?

i mean this is frustrating and it's taking the fun out of the hobby to be honest. 
its not fun with all this stuff crammed into it, people diagreeing, and apparently some math i dont care to learn, and restrikes, and level based light fall off, and... OI!

thats why i wanted to know really what would work or rather get me 3 to 3.5 WPG or whatever i need for my high light plants or the equivalent of that, or whatever WPG i need. I mean i just want great looking tank while not going out of my budget.

i feel lost in a desert with no water. ignorance is truly bliss.


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## shalu (Oct 1, 2004)

You say for "Same watts". Yes if you have two bulbs, PC and NO light with SAME watts, then the TOTAL light each produces are nearly the same, maybe 10% different, but that will be over different size areas, however. PCs are TWIN tubes together and higher output from each tube. Each bulb produces more light over a compact space, 55w, for example takes up only 22". Now with NO bulbs, can you achieve the same compactness? NO. Don't confuse the two questions.

If you feel you keep getting the wrong answers, blame it on yourself for asking the wrong questions.

So let's say you use AHSupply reflector for T8 at NO. Each refelctor will take up 4 inches width, and each bulb at 32w nominal for 4 ft tube. How many can you pack them over the tank width and how many watt max can you get after removing the overhang wattage? then compare to PCs. If you pack the NO bulbs too tightly in the same reflector(impossible with AHSupply), you lose a lot of light due to restrike(same argument favors T5 over PCs). So with NO bulb, the upper wattage limit is much lower, unless you do ODNO.

One AHSupply 55w will be high enough light directly under it, not the whole tank. One crappy 55w pc fixture will,.... well....you will have to find it out yourself.


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## dennis (Mar 1, 2004)

You are over thinking this Ian. You can grow any plant just fine with CO2 and 2 watts+ per gallon. 

A 32 watt PC and a 20 watt NO will produce about the same amount of light. The difference is that the NO will be spread over a 3' distance and the PC will be spread over a 16" distance. A watt of light is a watt of light, the only camparision is in the light's concentration. This does not take into account reflectors or ODNO tubes.

You want a good light for your 29 gallon, and you don't want DIY as stated in an earlier post. My recommendation, go with any of the commercially available fixtures that give you about 2.5 wpg. or more. The hardest part with that is a 29gallon is 30" long and most fixtures are not made with planted tanks in mind, made doubly worse by the fact that 30" is very hard to light evenly. NO tubes are either 24" or 36" and PCs are around 16" and 22". 

My personal recommendation would be build a hood that holds either 2x55 watt PCs or 2x36 PC with 2x 24" NO tubes, one in the front and one in the back. You could also light it with a single pendant 150watt HQI....

As I said, the biggest problem with NO or ODNO is not the light output but the fact that all commercial fixtures(this includes T5) will leave some dark areas at each end, due to their being 6" shorter than the aquarium.

Personally I would not go over 2.5wpg until you get pressurized CO2. trying DIY with higher lighting is asking for trouble and is about 10x more work than it needs to be

Also, FYI....AH supply sells hoods for all sized tanks and their PC kits are so easy, an untrained monkey can do it. All you need is a screwdriver and a pocket knife. You really don't need electrical training or mechanical skills to to one. Plus, anyone who says they don't have the ability to do something relativly simple like that (i have heard people say they can't use screw driver) are not trying at all.

Or, metal rain gutter, easily cut with scissors, along with the gutter caps make excellent and attractive enclousures for DIY lighting. You could probably fit an AH 2x55 into one gutter if you mount the ballast remotely, which you should do anyway. If you have questions about that, call or email Kim at AH and he will be able to help you figure out exactly what you need, be it extra wire or whatever.

The easy DIY options are endless if you look around

Oh, and "i" when in reference to a person, especially when used in the first person point of view is ALWAYS capitalized.


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## david lim (Mar 30, 2004)

intensity is the rate at which energy is transferred per unit area, which we measure in watts per unit area. If you think about it, a 175W MH is very intense because the amount of energy used to drive the bulb is coming out of a very small area. Whereas with flourescent bulbs, the light is not as bright/ intense but more diffuse.

Now comparing PC, T5-HO, and NO, the NO's are the least intense because they use less watts to drive a bulb that has a larger surface area. Between t5's and PC's I believe they're essentially equal, with PC's winning out a little in intensity. However, the reason people are really looking into T5-HO (like myself) is that you can design much more efficient reflectors for a T5 compared to PCs. In the end, with reflectors, a T5 can be more efficient than a PC.

The disadvantage with a PC occurs because the tube is bent. An area is created between the linear tubes where light shines between themselves but never down to the tank. One could not conceivably build a reflector to utilize this light either. With a T5, however, one can build a reflector that utilizes the entire bulb. Also the reflector space should take up less space meaning you can fit more bulbs into the same area. 

David


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## urville (Sep 20, 2004)

ok.
This is all so much clearer to me put this way. Oh and I'm sorry I'm used to work where everyone types in lowercase. It's a hard habit to break and I'm so used to it.

I've got the tank filled and ready I have a nupro valve and I should get a basic bevarage dispensing regulator tomorrow, the one I got off of APD was broken. So hopefully thats covered.

i see what your saying about the using the 2 NO bulbs to offset the dark area of the 36 watt PC's. Are you implying that the 2 55 watts will actually light evenly? Am I just seeing that wrong? It was suggested if I was one pressurized that I might consider using a 36" 96 watt PC from AH Supply. That some light might be wasted but overall it would work well. Do you find that to be a true statement? On HQI 150w. I've read that you can control it a bit by the distance from the tank is this true?

And I can DIY, but not wood. I dont why but I cant seem to keep a straight line even when using my level, I think something I own is off a bit. Maybe I just have a problem with straight lines. Something. But when your building something that needs to rest on the top of the tank it ought to be level and well.. hehehe Most DIY projects involve tubes and silicone and drilling. Like the gutter. I actually wondered if white gutter would be a good idea since I could hang it above maybe about 3 inches, but most things I suggest lately end up being not good ideas so I just figured there was a reason no one was using it. White would be the right idea right? I notice the white ones are a bit more flimsy than the metal type. I dont think it would be too hard to spray paint it though.

I get now that what people have been saying all this time in far fewer words elsewhere is that the PC's are more light concentrated in one smaller area. I was mistakenly thinking they meant overall. I was getting the impression that a 20 watt PC was making more light than a 20 watt NO tube. I didnt understand. i thought there was some technology about them that enabled them to output more light per watt, but then you and Mr.Lim have cleared all that up for me. It's not that Shalu didnt say that, i just didnt get it from the way he was saying it.

And Shalu sorry, but I admit I get defensive and a bit irate. I had this same experience with Mr.Grigg, his post had a tone of "your an idiot" painted all over it. It felt like a deliberate attack on my intelligence. We all have our faults and I apologize.


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## david lim (Mar 30, 2004)

Mr. Lim?!? Please call me David. I think of my old man when you say that! lol

David


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## urville (Sep 20, 2004)

lol ahaha
i so saw you as that turtle from Finding Nemo


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## urville (Sep 20, 2004)

Kim says all kits come with enough wire and equip to mount the ballast 8 feet away from the ends of the bulbs.

He also said
"The 2x55w will not leave any dark areas in your 30" tank I can assure you. 
Just center both reflectors over your tank and the light will be very even 
throughout."

So I guess whoever said that the 2x55 would leave dark areas in a 30 gallon in another thread was mistaken.

I got my new regulator today a tapprite, only 42 brand new.


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