alright, im settin up a small shedroom... because of that im only tryin to put one hole in the side of it, (and cover it up with a false washer/dryer vent thing.) so which is more important, An exhaust fan to suck and pull air out... or an intake fan pulling air into the chamber... just registered not sure how to put up pics yet, but once i figure it out i will.. i plan on flowerin with a 400 w hps.. i have a 150 metal halide but it was used for my saltwater aquarium, the bulb is absolute daylight at 10,000 kelvin... is that too much?? if so im goin to use cfls for veggin... right now i have a 42 watter, and three 26 watters all in different pan light fixtures... how many plants could that amount of light support... absolute beginner so ANY advice is appreciated... thanks to all who respond...