hey mate, nice box.

you need some air circulation. Id get a fan and poke some holes. Intake at the bottom, exhaust at the top on the opposite side. you should have a 1.0/1.5 exhuast/intake diameter ratio. passive intake/fan to exhaust. exhaust vent your hps directly. It will help exhaust some hps heat and bring in CO2 and might raise the humidity depending on where the cab is set up. may also need a solution for smell depending on your location. veg with about 60% or so. keep the air a little wet. remember thou, when ya flower, drop the humidity, turn fan down. dont want to rot the buds.

Good Luck and Happy Trails!



hope that helps.