# T5 vs. power compact



## demosthenes (Aug 23, 2008)

right now i have a 10g tank with pressurized CO2 and an EI dosing regimen. My lighting fixture now is a 1x36W Power Compact by Finnex, with a 10000K bulb. It is really inconsistent lighting (by that i mean that one end of the tank is really bright and one is a lot less bright), and all of my plants become the exact same shade of green under these lights. 

I'm wondering if it would be worth it to upgrade to a 2x20W T5 fixture? Ive heard that T5 fixtures put out much more lumens per watt of light than PC's do, and then i could have more consistent light, and i think then i could use a 4500K light AND a 10000K light, so the plants would be a wider range of colors, right?


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## Left C (Nov 15, 2003)

The 36w PC is about 16" to 16½" long in your 20" aquarium. Couldn't you center up the bulb so that you don't have a dark side and a bright side, but equal sides?


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## Hoppy (Dec 24, 2005)

I use a 36 watt PC, AH Supply light, on my 15H tank, which is set up as a riparium. It gives very good uniform lighting since I have it mounted about 10 inches above the top of the tank. Two 20 watt T5HO bulbs would give far too much light unless that light is suspended way above the tank, like 12-16 inches or even more above it.


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## demosthenes (Aug 23, 2008)

Left C said:


> The 36w PC is about 16" to 16½" long in your 20" aquarium. Couldn't you center up the bulb so that you don't have a dark side and a bright side, but equal sides?


no, the bulb is centered exactly over the middle of the tank, and one end of the bulb is brighter than the other end. maybe i should just get another bulb then...



Hoppy said:


> I use a 36 watt PC, AH Supply light, on my 15H tank, which is set up as a riparium. It gives very good uniform lighting since I have it mounted about 10 inches above the top of the tank. Two 20 watt T5HO bulbs would give far too much light unless that light is suspended way above the tank, like 12-16 inches or even more above it.


right now it is about 1-1.5" above the water, depending on how long its been since i've topped off the water column, and a lot of my plants still show signs of not having enough light. also, for a high-tech set up, isnt 36W on the very low-end of lighting? some people on these forums have a lot more than 40W over a pressurized CO2 tank. i remember hearing about someone who had 96W over a 10g.
my


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## Hoppy (Dec 24, 2005)

demosthenes said:


> no, the bulb is centered exactly over the middle of the tank, and one end of the bulb is brighter than the other end. maybe i should just get another bulb then...
> 
> 
> 
> ...


The only valid measure of how much light you have is with a PAR meter. It isn't possible to use the wattage to even come close, unless you are just duplicating a setup someone else is using. One thing for sure, more light is rarely better light. If you have good CO2 and fertilize so that no nutrient limits the growth, you get good growth with a lot less light than people used to think was necessary. A 36 watt AHS PC light gives high light intensity on a 10 gallon tank, so much so that the light needs to be raised a bit to avoid lots of algae problems.


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## Left C (Nov 15, 2003)

demosthenes said:


> no, the bulb is centered exactly over the middle of the tank, and one end of the bulb is brighter than the other end. maybe i should just get another bulb then...


Don't count the connector end that doesn't produce light when you center the bulb.

Center the two tubes of your PC that produces light. Don't center the whole bulb.

I have a 20" Coralife Aqualight with a 36w bulb. I center up the part of the bulb that lights up and it gives me equal lighting on both sides. My fixture is on mounting legs.


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## nsgrkg (Nov 2, 2009)

*demosthenes - love your bowfront tank!*

Mine is a corner 54 gallon. I am wanting to convert to planted tank. After much reading I was under the assumption that I would need much more light than 48 watts of T5 - was shooting for a fixture with 96 watts T5 lighting. Will this be so much that it will require CO2? I just want a simple setup planted tank.


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## Hoppy (Dec 24, 2005)

A standard 54 gallon corner tank is 38x27x22 inches. Is that the one you have? If so, you can use T5HO lighting, 24 inch long tubes, about 3-4 of them, depending on if you can space them a few inches apart and still get them on the top of the tank. That should give you high light intensity. Another option is a HQI pendant fixture. And another is 55 watt PC lights, probably 3 of them. All of those mean pressurized CO2 is needed.

To go with lower light so you don't need CO2, you could try just 2 T5HO single bulb lights spaced about a foot or more apart, or two 55 watt PC AHSupply lights, again spaced at least a foot apart. Those should give you medium light intensity, unless you suspend them about 2-4 inches above the tank, to get low intensity. Of course any light fixture will give low intensity if you hang it high enough above the tank. The high intensity setups above could be hung about 16 inches above the tank to get low intensity.


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## Left C (Nov 15, 2003)

demosthenes said:


> ... one end of the bulb is brighter than the other end. maybe i should just get another bulb then...


Hi

I had to do a double take on your above comment.

Are you saying that one end of the bulb is basically not lit up or dark looking? If this is the case, you do need a new bulb.

AHSupply has straight pin 36w bulbs in 5500K, 6700K and 10,000K for $15.99. These are usually cheaper than Coralife's 36w 6700K and 10,000K bulbs.
http://www.ahsupply.com/bulbs.htm


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## demosthenes (Aug 23, 2008)

Left C said:


> Are you saying that one end of the bulb is basically not lit up or dark looking? If this is the case, you do need a new bulb.
> 
> AHSupply has straight pin 36w bulbs in 5500K, 6700K and 10,000K for $15.99. These are usually cheaper than Coralife's 36w 6700K and 10,000K bulbs.
> http://www.ahsupply.com/bulbs.htm


Yeah, that is sort of what i meant. the bulb isn't obviously burnt-out looking on one end, its just that the lighting isn't evenly distributed. the end of the bulb is brighter than the pin-side, but it doesn't look broken. oh well, i'll try getting a new bulb. this one has been used for like 7 months now, so maybe it is burnt out. 

but then, what kind of Kelvin temp should i get? I'm pretty sure i have a 10,000K bulb now, but it looks too white, and all the plants are the same color. what do you have/recommend?


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## FSM (Jan 13, 2009)

6500k


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