# Two 26w CFLs -VS- Two 18w T5HOs...?



## Bebu (Jul 24, 2009)

So, I have a 10 gallon Perfecto Kit tank (20x10x12, canopy, and incandescent fixture) that I fitted with two spiral (or twisty) 26w CFLs. I have pressurized CO2 running on it as well.

The problem is that, 1) for the purposes of the planted tank, the spiral design is flawed or inefficient and the largest "U" shaped CFL (the longer, narrower ones) comes in at only 20w a piece. 2) The spirals are short and stubby so there is far less light in certain areas of the tank (middle, front, and far edges) because of where the bulbs are situated in the ballast that sits on the kit's canopy.

Now, at the LFS, there is a 20" ballast with two 18w T5HO bulbs. I was wondering if two 18w T5HO bulbs that reached across the entire tank would be better then the two 26w spirals.

Input is much appreciated.


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## solarz (Aug 31, 2010)

The T5HO are definitely better, but I wonder if you could improve the CFLs by putting in aluminum sheets as reflector?


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## Bebu (Jul 24, 2009)

Hey, thanks for the reply... I did in fact use aluminium foil as a reflector, but the difference was negligible. I could go even bigger in wattage, but the ballast or light socket is only rated at 25w x 2. So, I'm already over by 2watts..


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## Rmwbrown (Jan 22, 2009)

Two T5 HO tubes on that tank could prove to be quite a bit.. you would really need to maintain the Co2 and keep up on your dosing or it could become pretty nasty pretty quick. Do you have a way of adjusting the the height of the fixture above the tank to suit your needs? If so, that could prove very useful.


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## ThaChingster (Feb 25, 2011)

try to see if the T5HO fixture can run with 1 bulb, that'll help out a lot


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## Bebu (Jul 24, 2009)

Rmwbrown said:


> Two T5 HO tubes on that tank could prove to be quite a bit.. you would really need to maintain the Co2 and keep up on your dosing or it could become pretty nasty pretty quick. Do you have a way of adjusting the the height of the fixture above the tank to suit your needs? If so, that could prove very useful.


As far as movement of the fixture, its impossible, or impractical really. I don't know if you've seen the Perfecto (more like crapo..) kits, but the fixture slides right over a sleeve that is fitted with glass on the bottom. The problem is that its very narrow and therefore the light isn't allowed to spread as it would if it was suspend from the ceiling over a open top tank...

Really? You think 3.6watt per gallon is too much, even with the pressurized CO2? I didn't think it would be. What watt per gallon do you guys run at?


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## solarz (Aug 31, 2010)

Bebu said:


> Hey, thanks for the reply... I did in fact use aluminium foil as a reflector, but the difference was negligible. I could go even bigger in wattage, but the ballast or light socket is only rated at 25w x 2. So, I'm already over by 2watts..


Hmm... how high is your water level? Try lowering it.


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## Bebu (Jul 24, 2009)

solarz said:


> Hmm... how high is your water level? Try lowering it.


Well, I can't really. The tank is quite shallow, and the return spout is very close to the surface already. If I lower the water level, the spout will start splashing which will most likely 1) make noise  and 2) splash water onto the glass cover and surely will build calcium or some sort of crust or other...


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## Greg_o (Mar 4, 2010)

re: Aluminium as reflector, apparently it absorbs too much light to be of any benefit, according to Rex Griggs site.


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## Rmwbrown (Jan 22, 2009)

T5 HO is a whole new ball game... WPG rule doesn't hold.



Bebu said:


> As far as movement of the fixture, its impossible, or impractical really. I don't know if you've seen the Perfecto (more like crapo..) kits, but the fixture slides right over a sleeve that is fitted with glass on the bottom. The problem is that its very narrow and therefore the light isn't allowed to spread as it would if it was suspend from the ceiling over a open top tank...
> 
> Really? You think 3.6watt per gallon is too much, even with the pressurized CO2? I didn't think it would be. What watt per gallon do you guys run at?


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## Bebu (Jul 24, 2009)

Rmwbrown said:


> T5 HO is a whole new ball game... WPG rule doesn't hold.


So, would you recommend running only one of the 18w T5HO bulbs? Will that be enough?


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## Rmwbrown (Jan 22, 2009)

Whoever suggested that is working under an untested hypothesis. Most of the T5 lights, unless each tube is an independent circuit ($$$$), require both tubes finishing the circuit to create any light whatsoever. Small tanks need a a great deal of light to meet the minimum threshold and you do have pressurized Co2, so it may be worth giving a try.


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## Bebu (Jul 24, 2009)

Okay thanks!


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