I was going to get one of those while back and it stated 200cfm on another site i found it was half that..theres a few calculators on net to measure cfm of room mine was around 170 odd cfm so i bought a 330 cfm fresh hyper .i doubled it cause theres a few variables to consider.bends and length of ducting aswell as the carbon canister.i run it roujghly about 40% having it bigger means you can turn it down on controller for less noise..if you have heat issues you can turn her up
I ran into those when i got started too. I think i read to use the proper fan in grow weed easy dot com. Big difference. $35 helper fan $90 inline fan.
I payed a little more and got hyper fans too but one of them has become noisy and doesnt always start back up after about 6 years. Shouldnt complain. they burn less power and move more air than the cfm says. I wanted to replace but they cost over $200
flu inflation price. Payed $130 before. But my 400cfm hydrofarm active air fans dont cool my room quite as well.
On topic i could use a duct helper fan to help move the exhaust to my chimney. It is kind of a long awkward run.