I've had this pump for a couple months now, on my 10" shallow frag tank and it seems to always create micro bubbles. When I put it on feed mode, the pump stops and purges the rest of the air, then runs clear for a while. Seems like I have to do this at least once or twice a day to keep the tank clear of bubbles. I've watched it closely and it doesn't pull air from the surface at all like if it was too close to the top. Anyone else have this issue and have been able to fix it?