That bulb is around 8" long, right? If so, I would put it at 7-12" away. Is it 6400k or 2700k? If the nodes start to gap too much, you could lower it, but I wouldn't go closer than 5". Those small 18-25w bulbs, like in the pic above, are the ones you read about that growers put real close.Whats up guys, I got a 125w cfl bulb with the light fixture and was wondering how far away I should put it from my little 1 inch stem with the 4 leaves..