I had a pool installed last year and from the beginning I have had air bubbles in the pump basket and coming from one of the return lines. The builder has done two leak detection tests and everything seems to check out fine. I run the pump at 1800 RPM's 24 hrs a day (at their recommendation) and the air bubbles are there. I have noticed that if I put the RPM's up to 2700 it runs fine with no bubbles in the basket or from the return. I have read that at low RPM's I can expect to see some bubbles. Should I be experiencing the air bubbles at 1800 RPM's? Any ideas on what I can do to stop the bubbles?