Okay....i have 2 8inch fans blowing thru my lights........with a 12 inch fan pulling ..........i have to 12x8 inch holes in my walls with 6 inch adapters with 6 inch ducting to allow free air movement......which i though would allow the 2 fans to pull air from them since they are free air vents.....but what happens when i turn the fans on ......the room starts to pull in ......i have 3 soild walls with white mylar on them.....then i have 1 wall made of the white mylar....the room just sucks in.....i put a piece of tissue to the vents and no air movement at all.............i was thinking of attaching 8 inch ducting to the fans and attach it straight to the 6inch ducting of the vents and pull it straight thru....but what about the having fresh air in the room.....?.......need answers quick because this is the flower room....and i just placed them there without checking the ventilation with the mylar wall.......