what cfm exhaust do you have, maybe its not pulling enough heat out . i had a 265cfm pulling through an air cooled hood and a 3x4 grow box and didnt have a problem. i think its your cfm's postman. ps dont use a bathroom exhaust fan in your box. and if you having a problem with you heat you should get 1 of these, with summer coming around. you dont wanta be homeless with a fire outbreak.

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