Hey Damien the 4" fan is more than sufficient for a 2x2x4 tent.I new too, just finishing my first grow. I have a small tent also, 2x2x4. I heard from a youtuber who seems to give good advise 4" carbon filter fans don't move very much air at all, nothing smaller than 6" should be used. Is your 4 incher circulating good enough in the small tent your growing in? I want to use a carbon filter next grow, but would rather use a 4" (I'm on a tight budget).
Don't waste your money.
Just make sure you keep the cover on the filter.
Then clean it after every grow.
You will be fine.
Was the Utbr selling something or trying for more followers to improve his status regardless of poor advice?
We have nothing to gain by giving advice here.
Just the satisfaction of helping someone.
Take that into account when you go to these monetary sites.
My door is always open if you need anything my friend.
Stay safe
Bill