T5 Fixture for low/medium light

Harry Muscle

Junior Poster
Mar 17, 2007
I've been doing lots of research lately trying to choose a light fixture for a new 20G High (24x14x16) that I wanna get. I'm planning on making it an open top tank and would like to use a T5 light fixture since it's hard to find nice T8 fixtures that give enough light and PC fixtures heat up like crazy.

The question I have is whether my idea will create too much light and will require CO2 and/or constant Excel which I'd rather not do since I'm planning on setting this tank up using Tom's Non CO2 method described in the Articles section.

I really like the look and price of the Current USA Nova Extreme T5 HO 2x24W fixture, however, based on answers to some of my other questions (on TPT) it seems like this would put me in the high light category. My other choice would be the Coralife Aqualight T5 NO 2x14W fixture, however, the look and especially the mounting options (ie: no real legs available, just wire supports) don't thrill me. I'd much rather try to make the Nova Extreme work for me if I can.

So the plan would be to change one bulb to an actinic bulb in the Nova Extreme fixture, since it puts out very little usable light for plants thereby reducing the actual light output. The idea behind this would be that assuming that an actinic bulb puts out approx 1/3 usable light as compared to a normal bulb and knowing that a T5HO bulb is about 90% as efficient as a T5NO bulb, it would produce almost exactly the same amount of light as the Aqualight T5NO 2x14W fixture, which from other comments wouldn't be too much light. Obviously I'd be wasting a bit of energy powering the actinic bulb, but my wife likes the blue light it gives off :)

So I'm wondering if others might be able to comment on my approach from a scientific point of view as well as from personal experience (since this would be only my 3rd or 4th tank :) ). Will my plan be asking for trouble (ie: algae)? Btw, I should probably mention that the plan is to have the light on legs, which would elevate it about 3 or 4 inches above the rim of the tank. Also I like floating plants so I plan on having a bunch of those (not the whole top of the tank, but maybe 1/3 or 1/4 covered with floating plants).