i have been using a few layers of this, with furnace filter material in between each layer. This stack of sheets are placed inline right before the outlet.

http://www.lowes.com/lowes/lkn?actio...990&lpage=none

I am sure I will need a bigger filter when i flower, but i still plan on using the prefilter to help. It works wonders!
MisterSource Reviewed by MisterSource on . How much negative pressure to control smell? I was thinking of running a small 60 cfm fan sucking air out of the cab to help control smell. With the size of my cabinet, this would exchange the air in the cabinet once every 5 minutes. Is this enough to control the majority of air leakage from the front doors of my c24(although much bigger) cabinet? I'll be using c02, so I don't want to to turn over too quickly because I'll be totaly wasting the co2. The air pickups for the scrubber will be up high above the c02 system. Once again, this Rating: 5