How high should I position my LED lights????

[noo2usa]

I just purchased 2X 120w LED units for my 120g. They are 440nm-460nm blue, royal blue and 8000-10000k white Edistar LEDs. 55 LEDs per unit. The tank is 24" deep. How far from the water level should I mount these? Everything I've read states that I'll be getting 14000-18000k total when all LEDs are illuminated. (3w powered at 2.2w each):hat:

 

[pumarjr]

i'd start them at 12" or so, then adjust as needed.