how big is your grow room/chamber a420? I thought about using comp fans but ended up going with a 7" household fan that I disaseembled and made a new bracket for to essentially turn it into a muffin fan like what your using. Im waiting until something actually smells before I get the carbon filter/make one. Im still working on getting the cabinet sealed so that the only inlet is a super fine heater/ac filter that i took apart and used the fabric to stretch across the inlet hole.