Air is locked (called enviormental roll ) in the tent = no Neg pressure, System not ducted correctly , the fan that is supplying the fresh air ,just let it supply in the room it self (remove intake to tent) Now what you have created is a positive presure room , Now I would need to know the CFM of the fan that is exhausting from the tent to really help but here is a base line on what is needed to correct your air flow , if is 200cfm you need to use or create a 8'' round opening in the tent, if the exhaust fan is 201- 500 cfm this opening would need to be 10'' round,then you will have crated a negtive pressure enviorment in the tent, if you follow my instuctions you will achieve close to a 1 min 100% air exchange ,and your tent temps will be with in a 2 deg dif from your positive presure room temp. I move Air for a living 30 + yrs exp.