Fans Intake/exhaust

Hey, I've been looking into inline fans and grow tents. Can't seem to find the exhaust/intake sizes on the tents I'm looking at. Are they commonly 6" or 8"? Also how many CFM separately (exhaust and intake) is recommended for a 3'x3'x8' tent?

Thanks

a couple of 450 cfm should do. I'd get one with a rheostat for the intake, and turn it down to around 400, and run the output a full 450, to create a little negative pressure.

What tents are you looking at? They should tell you the size and if not I would contact the seller to find out. It's probably a 6'' due to the size though.

You should be able to get away with just a passive intake. My fan/filter is 400 CFM with 8 ft of ducting going into the ceiling and it just does the job with a 400w HPS.