I was useing a Flor. 2 foot. I just put in a 150 HPS today. This will give ten times the Lums. I hope this will take care of the problem. BTW How much does it cost to run one of these HPS 18 hours a day? Appx. I don't need an exact.growing tall fast usually is a problem with the lighting is either to far away from the plant or just not enough (Strectching)