Distance to hang my 212W Taotronics LED Array?

[reefstarter]

I Bought a 212W Taotronics LED array, but am unsure of how far away from my tank I need to hang it. My tank is 36 long x 18 wide x 24 tall (inches). I plan to have a reef tanks with low-medium need corals, etc. What distance away from the top of my tank should I hang it? A quick reply would be awesome since my handy uncle is at my house for christmas who could help me hang it!!

 

[Cherub]

I keep my LEDs about 8 inches above the tank. Mine is a 48inch wide tank standard 75 gallon. I use two 180w panels with 3w LEDs and 90 degree optics. Mine are dimable and I keep the whites at 40% and blues at 75%. Hope this helps.