carbon filter and fan question

right now i have the 6 inch combo Growbright bright ass orange inline fan and the 6 inch Tall boy Filter from HTG.
filter specs are 9 1/2 by 28 inch long. my room is 10x10x8ish. my question is this, can i get an 8 inch and put it on the filter without any repercussions? like pulling too much air through that filter will cause less effectiveness? the filters are rated at a certain cfm? this is my first "tour de indoor" we dub it, and just getting everything dialed in... were going into transition and ...well more or less we had a pos pressure prob and was causing a scent. but if this neg pressure prob doesnt fix the prob just adding another combo like this would be advised? or just a 10 inch inline with a bigger filter all togather? input? thanks!!

My carbon filter went out last year and I bought one of those tall boy filters thinking it was a good deal n would do a decent job, total let down. Could smell shit almost immediately, ended up repacking my old one with carbon from petco and reinstalling it and used the tallboy as an intake filter since I couldnt do anything else with it. Still runnin like that today. Id spend the money on a decent 10" fan and filter for a 10x10 room, maybe a speed controler to dial in your pressure. its a pretty good sized area so your gonna be pumpin out a good chunk or odor and I wouldnt trust that tallboy for anything but an intake filter where all it has to do is keed dust n shit out, works splendidly for that.

if your filter is rated for 420 CFM for example just dont go over 420 CFM or it will not filter properly. using 420 CFM as the example i think its best to use a fan thats 420 CFM or less or get a speed adjuster on your fan where you can turn it down some. make sure you have the right flange to covert 6 inch to 8 inch if thats your duct size and fan size or whatever.