right now I have 4 white widows on a 4x4 tray under 2- 1000 w hps lights and I have the lights around 18 inches from the canopy and they couldn't be growing any better for me...I am actually thoroughly impressed (side note: I have completely removed all of the heat off my lights and I could drop them right down on top of my plants if I wanted to) I haven't seen any bleaching problems, hopefully they continue as they have