I should know better - but here's the dumb question anyway

harddon and zandor -- thanks for chiming in....
i'm growing in a basement -- a fairly large room. but it's the basement, and well, that smell rises. harddon -- i think your setup is ventilating a small grow room, correct? so you need intake on one side, exhaust on the other.

since i'm in this large space, i guess i need to simply exhaust the stink through an old dyrer vent (the squirrel cage fan would work for that). search ebay for it and you'll see what i mean. doing so would naturally draw clean air in (it hardly an airtight space).

zandor, what you're doing intrigues me. if what you're saying is correct (and i'm guessing a "fart fan" is a bathroom exhaust fan?), you just run that fan near the grow, with the filter somehow attached to the fan, and that removes the odors. that would be great. could you either explain exactly how you do it +/or if you have pics, that'd be great.
thanks again for both postings.
booch

It's just a wood box about 24�x18�x36� where you have air drawn in through the top with a furnace return grill about 16x20. Next you get 5 medium quality filters the ones with screen mesh on one side are the strongest. You can use 5 to 10 pounds of active charcoal from the fish store for each layer. I use 5 but next time I think I will add one more. You make a charcoal sandwich and use gray tape to seal the sides and make it one big thick filter. You build the box so the filters fit tightly on all sides. You have a stop of about ½� trim all around the part where the filters end so you can keep them in place and tight but do not restrict the air flow through the filter.

Next you have a 12â?� air gap between the bottom of the filter sandwich and another plywood sheet you attach the high volume fart fan (bath room fan) to the underside. This is about 18â?� from the top going down overall measurement. You should have about 18â?� of empty space for the return air to fill so you drill 2â?� holes along the bottom of the box for return air back into the room.

The idea is to pull the air through the filters clean the air with the coal and return the clean air back to the room. Mine is in the ceiling and has a duck return system back into the room. You need to build the same thing but in a self contained wood box.