Low/Medium light with T5HO fixture

H

Harry Muscle

AC Members
Apr 21, 2010
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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 good looking T8 fixtures that can go over open tops and PC fixtures seem to 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 Barr's Non CO2 method.

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 shouldn'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
smile.gif


So I'm wondering if others might be able to comment on my approach from a scientific point of view or from personal experience (since this would be only my 3rd or 4th tank
smile.gif
). 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).

Thanks,
Harry
 
Harry Muscle said:
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 good looking T8 fixtures that can go over open tops and PC fixtures seem to 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 Barr's Non CO2 method.

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 shouldn'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
smile.gif


So I'm wondering if others might be able to comment on my approach from a scientific point of view or from personal experience (since this would be only my 3rd or 4th tank
smile.gif
). 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).

Thanks,
Harry
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Why not just leave one of the bulbs entirely off instead of using an actinic? Why waste electricity if you do not need it? Will the light not work without a bulb in it? Don't know because I have never tried it. It just seems like a waste to run an actinic when you don't really need it.
 
fabsroman said:
Why not just leave one of the bulbs entirely off instead of using an actinic? Why waste electricity if you do not need it? Will the light not work without a bulb in it? Don't know because I have never tried it. It just seems like a waste to run an actinic when you don't really need it.
Click to expand...

Usually most 2 bulb fixtures won't work unless both bulbs are in. I'm assuming that's also going to be the case with this fixture.

Harry
 
I've heard that actinics can contribute to algae growth, especially bba. Your plan may work provided you use a conservative photoperiod. I'm thinking a low k rated bulb, something like 5000k might be a better match for the actinic than the 10000k bulbs that usualy come with them.
 
gmh said:
I've heard that actinics can contribute to algae growth, especially bba. Your plan may work provided you use a conservative photoperiod. I'm thinking a low k rated bulb, something like 5000k might be a better match for the actinic than the 10000k bulbs that usualy come with them.
Click to expand...

I've heard that too (actinics cause algae), but I've never actually seen any real proof (ie: someone try actinic vs normal and compare), always just hear-say, etc. If anyone has more info on this though that would be appreciated.

I think I'd also agree, that a lower temperature bulb might be a wise choice, balance out the blue somewhat. Too bad there's isn't such a thing as a bulb that gives off no light that I could use instead of the actinic :)

Thanks,
Harry
 
my nova extreme works quite well with only one bulb in. your problem may already be solved because of the fixture you have/want. also if you really like the cleaner/brighter/bluer look the 10,000k bulbs grow plants just fine. i'm using it on my low light - no co2 50 gal. and it's about perfect.
 
Actinic lighting puts out its energy in the specific wavelength in the blue end of the spectrum that plants use for photosynthesis. The belief that it doesn't benefit plants is flat out wrong. The blue end of the spectrum promotes bushyness as opposed to the red end that promotes elongation between the nodes. Photosynthetic activity peaks at around 680 nm on the red end and 430nm on the blue. A true actinic bulb peaks at 420nm.
 
blue2fyre said:
Why not go with a T5NO fixture? It won't put out as much light as the HO fixture.
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Unfortunately the only T5NO fixtures I'm aware of are the Coralife Aqualight ones, which unfortunately have crappy legs that don't elevate the fixture at all and because of that don't look as nice as other fixtures on an open top tank. And since this is gonna be in the living room, looks play a big part.

Harry
 
dundadundun said:
my nova extreme works quite well with only one bulb in. your problem may already be solved because of the fixture you have/want. also if you really like the cleaner/brighter/bluer look the 10,000k bulbs grow plants just fine. i'm using it on my low light - no co2 50 gal. and it's about perfect.
Click to expand...

What length fixture do you have?

Thanks,
Harry
 
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