correct me if im wrong... there are 2 total inline fans. one sucking air through the light and one sucking air out of the tent? you NEED to have a fresh air inlet into the tent. a few spaces i have built utilize 1 big fan acting as 2 parts and one small fan bringing in new fresh air. the big fan was hooked up 2 a y pipe, wich was pulling hot air from my cool tube and from the room at the same time.the second fan was bringing in fresh air. your circular fans are there to act as wind and help keep the temps balanced.just remember your re creating nature.when i was trying to sart my own little buisness doing hydroponic bell peppers i had my inline fresh air fan fail and destroy my entire crop in less than 4 hours whal i was out of town. it is vital to have fresh air flow.