im not 100% but when i had cloud he use to go to the top alot....but thats because he was always above the filter when i was not near his tank lol, i think its something you shouldnt be worried about as i think its healthy enough....
the best air pump is tetratecs, I have one thats up to 60l tank and my god its quiet!
I dont use it mind as bettas dont like too much flow
do you mean filter or air pump?