I just purchased a 400w hps lighting system but I'm concerned that the reflector isn't big enough (14"Lx12"Wx7"H) I have a 3'x3' grow space and plan to surround it with black/white poly. Is my reflector sufficient? If not, what else could I do to maximize on my light? This is the first time I'm using artificial lights and I'm not sure what is needed. Also, will the light generate too much heat? It's not in a closet, just a space I'm partitioning off in the garage(7' ceiling). Can I get black/white poly from Home Depot or something or do I have to order it? I'm trying to conserve money cause the light already set me back $230. I saw a 25'x10'roll priced at $30 plus shipping @ Discount Hydroponics. Isn't there some place cheaper somewhere? I live in Philly so shipping would set me back somewhat.