Can someone give me some advice on which light to get for a 3'x3' tent? I usually grow 3-4 plants at once. Right now I am looking at getting the old style 600 (or perhaps 2, if it isn't enough), or maybe the Mars II 700..I could only afford one of those. I don't know much about the reflector series, but I wouldn't be averse to those either, if they were cost effective.