# To add... or not to add. (2.6w to 4w and beyond...)



## Indignation (Mar 9, 2008)

Howdy. I have a 24 ga. cube aquarium with 2 x 32w PC lights installed in the hood(6700°/10,000°), and for the last few weeks, have been contemplating adding a third light. The plants i have (and would like to add) are mostly high light demand. Growth has been good for the most part, with some plants really taking off. The problem i've been having is any stems in the back seem to"reach" forward towards the lights, shading stuff in the mid-ground. 

My options are kind of limited, since the aquarium has a built-in hood that i would like to keep. 
#1. there is a mod available to add a third ballast/, with another 32w bulb. = 4 wpg.

#2. Or i could swap the 2 existing bulbs for a larger bulb...36 or 40w, since the ballasts are rated to 40w. = 3 wpg, or 3.33 wpg.

#3. Or i could go all kinds of crazy, and add the 3rd bulb mod with 40w bulbs all around. = 5wpg

So those are my options. I'm stuck between option #1 and #2, but i'm fairly new to this hobby, and would appreciate any insight you would like to share.


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## TortoiseBoy (Dec 30, 2004)

I am not sure I can help you choose between the options you have given, but maybe there are other options? Can you grow foreground plants low? For instance, does Glosso or HC grow flat? Also, is it an option to move the position of the lights at all? I found that by moving some of my light closer to where I needed it, this made a difference in the availability of light to the plants that needed it most. 

The only reason I suggest looking at all options before adding light is that you already have quite a bit and your tank is not all that deep. If you can't grow foreground plants, then that is one thing, but if you can, maybe you don't need the light as much as it might seem you do.

Finally, I am assuming you already have CO2. If not, 4 wpg is going to be a real challenge ;-)

TB


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## Indignation (Mar 9, 2008)

Thanks for the reply TortoiseBoy.

I am growing hc, and it is growing in flat, albeit slowly. 

There is a little room to move around one of the lights, but with the work it would take, i was wondering if it would be better to add a third light while i was at it. I was thinking of maybe only using 2 lights for the majority of the photoperiod, with the third light coming on for a couple hour "noon burst." 

I am injecting pressurized CO2 through a reactor, and am dosing using the seachem line and dosing schedule.


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## mikenas102 (Feb 8, 2006)

At one time I had a tank with over 5wpg. While it is nice to grow nearly any plant in the hobby it really does become quite tedious after awhile. At those light levels everything happens fast. Plant growth is almost uncontrollable and you'll eventually get tired of trimming all the time. Bad things can also happen fast and if you don't maintain a high nutrient level you have big problems.


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## TortoiseBoy (Dec 30, 2004)

Sounds like you have it pretty well figured out, Indignation. If you have pressurized CO2, it will be at least possible to keep the algae down. I agree with Mike, though, that 5 watts/gallon leaves small margins for error. You may be ok if you use the burst like you were thinking. Let us know what you decide and how it turns out :smile:


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## fastang80 (May 7, 2008)

With 5+ watts for gallon there's almost no room for error.


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## CraigL83 (Jun 6, 2008)

IMHO i feel the watts per gallon rule is virtually as useless as the fish per gallon rule. To explain my reasoning ill give you a scenario....Lets say you have a 65 watt power compact. The shape of the bulb is kinda like two fluorescent bulbs side by side. In order to direct the light down into the water you would use a reflector in order to obtain the max ammount of light in the area you want. Most of that light/power(wattage) will be lost because of the inability to direct the most ammount of light produced from the source in the direction you want just due to the shape of the lamp. The effect will be wasted light and wattage. Now lets look at a comparable 54 T5 lamp...the lamp is very skinny and can be fitted with a reflector that will enable you to maximize the total output of the lamp in a much more efficient way. You will actually find that you have more light at equal depths using a T5 lamp of less wattage in comparison to a power compact. So even though the power compact has a total of 11 more watts (in this example) the T5 of less wattage will produuce more intensity in the direction you want it to be. Sure adding another power compact wouldnt hurt...You shouldnt really refer to the watts per gallon rule because that is only relevant to the type of lamp you are using. You will need many more watts per gallon to achieve the same ammount of lumens at equivilant depths with power compacts in comparison to using various other lighting setups.


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## Left C (Jun 14, 2005)

Indignation said:


> ... #2. Or i could swap the 2 existing bulbs for a larger bulb...36 or 40w, since the ballasts are rated to 40w. = 3 wpg, or 3.33 wpg. ...


I believe that your 32w bulbs are square pin bulbs.

I would swap out the 32w bulbs for either 36w or 40w PC's since your ballast is rated for 40w bulbs. You will also make sure that they will fit. This would give you 3.0, 3.2 or 3.3 wpg depending on the combination choices with these bulbs.

I have a Coralife 28w PC fixture and it's ballast is rated for 40w. It will also run 32w, 36w and 40w square pin PC's.

Here's two choices. Both of them are very good bulbs. I'm using both of them.
1) Current's 40w dual daylight 6700K/10,000K bulb. (Model 2024 40 watt Dual Daylight 6,700K/10,000K 16.75" x 1.75" x 1") You already know what they look like.
http://current-usa.com/sunpaq.html
They're on sale at DFS.com for $16.49.

2) ADA's 36w 8000K bulb It has a nice, crisp white color. It is 3/4" shorter than the 40w bulb.
http://www.adgshop.com/8000K_PC_bulb_p/108-060.htm

I have a 2x40w Orbit fixture with both of these bulbs in it over a 15g tall. I've also used two of the 6700K/10,000K bulbs together and two of the 8000K bulbs together. All three of these combinations look good and grow the plants very well.

Here's some additional about these bulbs' dimensions. The measurements do not include the length of the pins. These are the actual lengths of the bulb that you can use to see if they will fit. I just measured them.
1) 40w 16 3/4"
2) 36w 16"


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## hoppycalif (Apr 7, 2005)

CraigL83 said:


> IMHO i feel the watts per gallon rule is virtually as useless as the fish per gallon rule. To explain my reasoning ill give you a scenario....Lets say you have a 65 watt power compact. The shape of the bulb is kinda like two fluorescent bulbs side by side. In order to direct the light down into the water you would use a reflector in order to obtain the max ammount of light in the area you want. Most of that light/power(wattage) will be lost because of the inability to direct the most ammount of light produced from the source in the direction you want just due to the shape of the lamp. The effect will be wasted light and wattage. Now lets look at a comparable 54 T5 lamp...the lamp is very skinny and can be fitted with a reflector that will enable you to maximize the total output of the lamp in a much more efficient way. You will actually find that you have more light at equal depths using a T5 lamp of less wattage in comparison to a power compact. So even though the power compact has a total of 11 more watts (in this example) the T5 of less wattage will produuce more intensity in the direction you want it to be. Sure adding another power compact wouldnt hurt...You shouldnt really refer to the watts per gallon rule because that is only relevant to the type of lamp you are using. You will need many more watts per gallon to achieve the same ammount of lumens at equivilant depths with power compacts in comparison to using various other lighting setups.


The "watts per gallon rule" isn't a rule, but a guide for getting in the right ball park for enough light. You really have to say what type of lights and reflectors you are using to make a "2 watts per gallon" statement mean much. T5 lights, with good reflectors, definitely do give more light intensity per watt than PC bulbs. It appears to me that you can assume that you get around 50% more intensity using T5 lights. And, any bulb, with no reflector is not going to give as much light intensity as one with a reflector, even a white painted reflector.

But, without some kind of "rule", you have no place to start when deciding what light to use on a tank you are just setting up. You can always find out the wattage of the light you are considering, but only rarely can you find out how much PAR that light will give 20 inches below the fixture. So, we start with watts per gallon.


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## Indignation (Mar 9, 2008)

@ Left C - What you suggested was the route i ended up going. I purchased 2 40w Current Dual Daylight (6,700/10,000k) since that is the same type bulb currently in the fixture, and one that I've been happy with. The length is going to be close, but i found a journal by someone who had tried something similar on the same tank with a reef setup. Link.

I plan on just using 2 bulbs. Hopefully by going this route I can up my light a little bit, while also solving the issue of stem plants in the back trying to grow forward - when remounting the end caps, I can also move one of the lights back a little. 
I appreciate the detailed answer and info though, thanks!

@ Craig, Hoppy - The "reflector" (a flat piece of polished aluminum) is kind of a joke on this tank, so the wpg rule is not as applicable. Like Hoppy said, it does help to give a general ballpark though, something that a new enthusiast can use as a starting point.

As an aside for future forum-searchers like myself: I purchased my Aquapod 24 before I knew anything about planted tanks. It has been challenging, to say the least. The tank is beautiful, and if you like the DIY stuff, it's a great all-in-one solution. If a high-tech planted tank is what you are going for, and you want keep everything hidden in the back chambers, I would warn against it for anyone lacking abundant patience. But if you do, the end results will pay off.


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## CraigL83 (Jun 6, 2008)

Whether you want to call it a "rule" or a "guide" doesnt make any difference....whatever you want to call it i think i made the same point that hoppycalif pointed out.


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## Left C (Jun 14, 2005)

Indignation said:


> @ Left C - What you suggested was the route i ended up going. I purchased 2 40w Current Dual Daylight (6,700/10,000k) since that is the same type bulb currently in the fixture, and one that I've been happy with. The length is going to be close, but i found a journal by someone who had tried something similar on the same tank with a reef setup. Link. ...


I hope that the dual daylight bulbs will fit.

If they won't fit; the ADA 8000K bulbs are 3/4" shorter.


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## Indignation (Mar 9, 2008)

I finally got around to adding the lights - from 2x 32watt to 2 x 40 watt Current dual daylights. I didn't grab a picture before i put the splash guard back on, but there was some serious modding involved. I had to cut and re-glue the reflector, move a ballast, end caps and moonlights, and re-run some wiring.

Here is a "before" picture (not my pic or tank, thanks Natureboy for pic) 









I hadn't tried anything like this before, and I'm pretty happy with the final results:

















After having the lights up and running for 2 weeks, I'm very happy with my decision to increase the wattage. My stems plants are growing straight, everything is pearling much sooner, and oddly enough, my hair algae is receding. I switched to EI dosing several weeks earlier, so this could have just been the plants finally out competing the algae and be unrelated to the lighting.

Here's the tank with the new lights in it:








Kind of sloppy at the moment, I'm just letting some stuff grow out so I can re-scape. Wish i had a decent "before" picture, the entire left side (where the powerhead and R. Goias is) was shaded.

Thanks again to everyone for the advice.


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