Thanks for the replies Opie. I'll take it into consideration. I'm trying to get a continuous grow going, with both a veg and flowering chamber... and I can really only afford the one 600w HPS at the moment. Also, electricity usage is a problem. I don't have a limit on my apt, since I pay the electricity bill, and the breakers are in my apt... only problem is, I don't know whether I could afford to have a MH and an HPS going at the same time.