Air coming through the returns


LifeTime Supporter
Mar 29, 2007
Burlington, NC
Almost every time I clean out the pump basket, I get air bubbles through the returns when I restart the pump. This usually lasts for several minutes and then clears out. When I shut off the pump, I then turn off both skimmer valves and the main drain valve before I open the pump basket.

Are the air bubbles normal or an indication of a potential problem?



chem geek

TFP Expert
LifeTime Supporter
Mar 28, 2007
San Rafael, CA USA
This is perfectly normal.

Even though you shut off the valves to the two suction pipes (skimmer and floor drain) there is still air introduced into the system when you open your basket. Remember that you first open the pressure relief valve before you open the basket lid and that lets some air into the filter. The basket lid being open also lets some air into the filter. With anything open to the filter, water is able to at least partially drain out to the returns. When you then close everything up and open the valves and turn on the pump, the pump primes (water comes in through the suction pipes) but the air in the basket and filter is pushed through to the returns.


LifeTime Supporter
Apr 3, 2007
East Tennessee
If the bubbles are short lived I dont see a problem. Most sand filters with the rotarty valve have a bleed valve on them. You might bleed some of the air off using this valve. You will loose some water in this process so unless it is a real anoyance I would just let the system prime it self. Also dont unscrew the valve too far or it will come off in your hand (had it happen to me).