Why 2 exhausts? The carbon filter is supposed to go on your exhaust, which should be your only exhaust. It goes...Filter------>Fan----->outside room. No air that has not been thru the carbon should be allowed to leave the room. I only have 1 exhaust, a 172 cfm fan and a home-made carbon filter and that works fine....(with cfls, I have a 400 watt air cooled hps for my soon to be used flower room!!) You don't need an axhaust AND a filter, the filter is for the exhaust. the idea is to scrub the air as it leaves. I vent my air right outside and the front porch it vents under is odor-free. I know I'm not in flower yet, but they do stink pretty good..(before I hooked up the carbon filter, I smelled it 2 rooms away!!) I can't really picture your setup. You have an enclosure of panda film in the closet? Just use the fan and filter combo as the exhaust, you don't need another!!! Hope this helps.