Black box question.

[RadUReefer]

Hi all! New to the community and had a question about using a black box light. I purchased a used 75g tank (48long) that has a canopy. There is about 6 inches from the bottom of the canopy to the glass lids that cover the water. I see that many people hang their lights but I am wondering if I can mount a 165 or 300w light inside of the canopy? I would like to grow softies and lps and wondering if that is to much light to close to the water? Like I said I'm new so go easy...just trying to get up and running with some success with the so called easy stuff...

 

[TopShelfAquatics Verified Sponsor]

You have to be very careful with the black box lights. While a lot of them will grow corals well. They can be very over powered. I would definitely start them out at low power until you see how your corals react to them.

 

[BeejReef]

On a 4' tank, you may do better with two 165's over one 300w.

Generally speaking, the higher the better, so long as you're still getting enough light to the bottom of the tank. U can def mount them higher up in the canopy. It's nice to have a canopy for exactly that reason. You can get em up nice and high and not have the excessive light spill you would have with lights hung exposed over a tank.

 

[RadUReefer]

Thanks for info all. So just to be clear would I be ok to mount the lights only 4-6 inches above the waters surface as opposed to the 8-12 inches that everyone seems to use? If so, I am assuming I would just turn them way down?

 

[AbjectMaelstroM]

Thanks for info all. So just to be clear would I be ok to mount the lights only 4-6 inches above the waters surface as opposed to the 8-12 inches that everyone seems to use? If so, I am assuming I would just turn them way down?

Yeah would need to turn them down. Also you may run into some color separation and hot spotting.

Do you have access to a PAR meter?

 

[RadUReefer]

Yeah would need to turn them down. Also you may run into some color separation and hot spotting.

Do you have access to a PAR meter?

Thank you.. No access to a par meter.

 

[BeejReef]

I'm not fully understanding your question?

Why do you want to mount them so low? You certainly can, but on a 4' tank, if you stand back, you will probably have visibly bright and visibly dark areas. A par meter (if you could get one) may well show that the contrast is even more pronounced than your eye can see.

I'm just saying that, all things being equal, you're very likely to be much happier with them up significantly higher, and with an enclosed canopy, it won't look any different either way. Is there something about the design of your canopy that makes a lower install way easier?

Those black boxes really pack a punch. You're very unlikely to be hurting for par at whatever height you choose.

 

[Nicholas Dushynsky]

You can take the light apart and remove the lenses (ease of this depends on which black box), this would cut down on any hot spotting and in turn will reduce par and the colours will be mixed better. So years its doable and would be easier to do if you have access to a par meter.

 

[RadUReefer]

The canopy that came with the tank is very shallow. It is only 6 inches in height so if I wanted to keep it and mount the lights inside of it ..they would only about 4 inch's from the surface of the water...it is certainly am option to not use the canopy but that mean storing it and I don't really have the space. Hence why I was asking if a light could be mounted 4 inches from the surface of the water. Hope that makes sense. Thanks for the replies.

 

[EMeyer]

This sounds similar to one of my tanks. I think my canopy may be 8" but very similar. Nothing wrong with hanging black boxes close to the water, just turn them down as has been said already.

I agree with what's been suggested - remove lenses, use two 165s instead of one 300W.

My 2c

 

[RadUReefer]

This sounds similar to one of my tanks. I think my canopy may be 8" but very similar. Nothing wrong with hanging black boxes close to the water, just turn them down as has been said already.

I agree with what's been suggested - remove lenses, use two 165s instead of one 300W.

My 2c

Appreciate the advice. Now just need to pick one out!

 

[AnthonyN]

This sounds similar to one of my tanks. I think my canopy may be 8" but very similar. Nothing wrong with hanging black boxes close to the water, just turn them down as has been said already.

I agree with what's been suggested - remove lenses, use two 165s instead of one 300W.

My 2c

I am doing the same thing as the OP is doing. My question is what does removing the lenses do. I am more than willing to remove them or replace with another lense. Your thoughts?

 

[R33FLIF3]

Ditch the canopy! 14 inches from surface.