Pump off - air bubbles return jet

[611Manetta]

I just started to notice as of last night that with my pool pump OFF, that I am getting air bubbles coming out of my return jets. How is this possible? What can be wrong?

 

[Poolbreh]

Are the spa jets or pool returns? Spa jets maybe your air blower was on. Pool return we would need a better understanding of your equipment.

 

[611Manetta]

Pool return, we don’t have a spa.

 

[Rancho Cost-a-Lotta]

How long do the bubbles continue before stopping? Big or small bubbles? Does you plumbing hold water when the pump is off, or can you hear water draining back to the pool?

Your SWG does create hydrogen gas bubbles when operating, but make sure the SWG is shutting down when the pump is off.