I was talking with the president of the general hydroponics chain and he told me that there was a study done at the University of Alaska where to bulbs side by side do to a fanominon called photonreturn can cancel the light out and actually shut off the bulbs. He is extremly techniqel and I was having a bit of trouble following as he uses alot of scientific term but that was the jest of it. Next time I am in the area I will stop in to see him and ask him to explain it to me again. He has explained it to me twice so far but he is very nice and I am sure he would not mind explaining it again. I have to go see him in the next couple months about some thing else so I will keep you posted.