Unfortunately most components used in the the Aqua pod, or JBJ NAno and other items is bare minimum in quiality or price just to get buy. Every now and then they do manage to get a decent fan or component that is perfect, but its the norm for the most part. I would look into seeing if the fan itself is secure in its mount, and that no dust is built up on it. Ensure its opeing is not obscured (like you stated not fully cut out). If everything checks ok, I wuld ocntact Current USA and tell em its unacceptable, and odds are they will send a replacement fan which may or may not be any better. Current USA is real good abaout taking care of any problems as such. If yu just happen to wind up with yet another noisey fan call em again and complain, or just buy a higher quality replacement fan from an online or local source. This is perhaps the best option, as its not hard to find better fans that what is normally used my manufacturers, and they are not expensive.