PLZZ..need help,advise, on temps. !!!!!

Have a plea here for some advise from seasoned growers: 2x4x7 tent,400 watt glass air-cooled light,6"fan(500 cfms/w speed controller at lowest setting,no carbon filter yet, couple of small fans. Have one side of hood ducted and other open to suck in fresh air from passive intakes. With fan on all the time it's only 63 (to low). With fan off it goes 85 fast.

Should I duct the other side of the hood and just draw air from outside for the light w/ a thermostat on the fan? Put a small 4" exhaust in top to bring in fresh air.

Take glass out of hood? Let hood suck air in? Fan sounds like it might be exhausting to much to fast and just dropping temps to low.

Tent is in basement by window so plenty of fresh air to be had. 3 intake flaps at bottom of tent, maybe tape up a couple? Just looking for the right combo here. Thank you very much...........
 
Top