I have the aqualight pro.....150w halides (3) with actinics(4) 96w. (7 inches off of the tank) It is directly under one of the halides, probably 12 inches below it, maybe I should move it,? but at the store it was under a 500w halide. It came already attached to the clam shell.
Shrimpi, I miss your mandarin avatar....but your harlequins are beautiful, I posted in your section on these. Good luck with them, mine has been a real benefit in the tank.