Air in the system

[swimdaddy]

If air is getting into the system with the pump off, wouldn't that have to occur above the water line? If there was a leak below the water line, than the pressure of the water would push water out, not air in, right? I know I am probably wrong, just trying to stimulate further conversation.

[Phillbo]

I found the culprit. It was the backwash valve. It was cracked and allowing air to enter the system once the pump shut off (found this by accident when i had to replace the valve due to the handle snapping off). New valve and o rings and there is no longer air in the system when it starts up in the morning.