It's better to draw through the filter than to pressurize it , the carbon gets a chance to do it's job then .

I have a 6 in. x 18 in. filter from this seller . It works great and I've ref. quite a few ppl. to her on other forums . I don't know if the lil self contained comp. fan ones work well , but the canister filters do . Her names Kim BTW and she'll bend over backwards to make you happy , even shipped mine empty so I didn't have to get bent over shipping the heavy ass carbon as I can get pelletized stuff here local for crazy cheap .

Yes you can run the filter and cool your hood using the same blower . air -> filter -> hood -> blower . Don't expect to do it using a 20.00 30.00 inductor booster fan though . Use a Vortex , Hurricane type blower . How long is all the ductwork , how many sharp bends in it etc... will all affect the filter , and blowers ability to do it's job too. I used a 449 cfm 6in. Vortex and had no probs. .

I started doing huge hydro grows though and ran into probs. as the carbon absorbs all the humidity / moisture and the filter no longer can do it's job then .

Peace
Crispi :stoned:

PS. - Naughty Dreads - they do come w/ a pre filter , or atleast mine did , she just doesnt picture it so you can see how the filters constructed .