I thought that I had read in Jorge's Bible that you want to keep the light about 12 inches away from your plant. Even if you are at 12 inches then you would be getting some great lumens anyways. Your bulbs rating is taken at 12 inches from its glass. So my 600 has like 90k lumens and thats measured at 12 inches. I dont know about you guys but I am not that greedy lol, I am with secret on this one. I think that lower portion would not like the loss in light.