Quote Originally Posted by badflash
I think you should pump air before & after the bio filter. The bio filter eats oxy to work and can deplete the oxygen from the water. Giving it a boost after gets the O2 up for the fish.
As long as the bubbles travel through the water after the bio filter there should still be some o2 getting into the water. I've been meaning to try a baffled box to slow down the bubbles to give them more time to exchange o2.