I appreciate the input Erysichton. I've been checking out the the mini systems that will allow you to alternate between mhs and hp by flipping a switch and changing the bulbs. Their about 200 dollars for the whole rig(both lights).These are both 250 watt My cfl setup at this time raises the grow box temp approx. 8-9 degrees above room temp. Again, never did this before and it seemed the cfl's would be safest route. with size, space I'm using, as well as cost effectiveness. Still considering flowering with the hps. Just didn't want to get so close to bud and fry em. What size room/box are you using with the 600 hps? Does it remain stationary? And 1 last question. How are you venting/running fans. At this time I have my setup in a spare room, using basically a ceiling fan and floor fan to keep air moving. I have em in a box to insure I can lock everything down if there comes a need. Thanks again for all the input.