So this is my first post along with my first saltwater reef ready tank with a sump (not my first SW tank). So the tank has been up for roughly 4 months now and i still have a TON of micro bubbles from my oulet side. We had a 29 gallon before this 90 that we used as the sump. plumbing ont he sump is all hard piped using pvc, 1 1/4 on the drain side and 3/4 on the return. return pump is a mag 9.5 (got the pump used). Heres the issue, i have a bubble trap, zero bubbles are getting into the return section of the sump. a little about how the sump is set up. the tank drains into the left side, in that chamber is also the protien skimmer, from there it goes through a bubble trap and into the return section. water gets pumped out to a y fitting and one side goes to a refugium in the right side of the sump and drains back into the middle return section. The other section of the y goes back to the DT. I have ball valves to control the flow through the refugium and also to the DT. If i have the ball valve open more than halfway to the DT i get SO many bubbles its unbearable. The more flow, the more bubbles, the less flow the less bubbles. No water leaks at all in the return side of the pvc. Like i said this tank has been up for 4 months now so i would have seen leaks by now. I have tried everything from runnign a filter sock, to putting foam in the bubble trap to shutting off the flow to the refugium, turning off the skimmer, nothing seems to make it change, could there really be air getting in the return side???? Is my mag 9.5 bad??? I just dont get where these fregin bubbles are comming from. Please help, i will try anything.