Diy led

Hey everyone! I'm building a lighting fixture for my brother in my AP Phyics class, and I need some help with finding out how many watts I need. His tank is 12dx12wx24l reef tank, and he wants to keep SPS. I'm going to use Cree LEDs, a mixture of cool white, royal blue, and blue, but I don't know how many 3 watt lights I need.

PS- I know there are several DIY kits out there, but I am not interested in them. I only need help with wattage.

 

I believe that is about a 15 gallon tank right?

With LEDs it's hard to give a general wattage number. Depends on a lot of things such as tank height, how high you're going to hang the fixture, aqua scape, optics, and what not.

If he wants to keep SPS, I would say 12 LEDs should work. Depending how high you put the fixture, you might not need optics since it is pretty shallow. Over my pico, I have no optics and they hang about 14'' from the bottom of the tank. I have a clam at a foot from the LEDs and it is doing great. There is some noticeable light spillage though. Could hang a little higher and use 90 degree optics.

 

Yeah it's a 15. How high above do you recommend?