Carbon fitlers and CFM's

I have a 6" booster fan doing about 280cfm and was thinking about getting a carbon filter for a 3x4x6 room. The fan and duct line is currently only acting as a heat exchange and would be easy to put a 6" carbon filter on the end of it or i could reduce it to 4" and get the 4" carbon fitler.

Was thinking of getting the HTG one but didnt know what the proper size would be.

Would 280cfm be enough air flow through a 6" filter? Any body have some personal experience that would be great.

http://www.hydrofarm.com/pb_detail.php?itemid=10891

That one is rated @ 150cfm for scrubbing.

I would get a inline fan and not a booster fan. Even inline fans drop the amount of CFM then can pull a lot with a carbon filter. I would get a cheap inline fan, like 90 bucks from htg and use the booster. If you are going to cool your hood id do it like this: filter===booster===hood====inline===exit.