A few days ago I noted a suction-side leak on my Hayward Ecostar variable speed pump. I replaced and lubed all gaskets in the two Jandy valves leading to the pump (one small gasket was broken). I also checked, lubed and tightened the two drain plug gaskets in the pump. I also removed the basket lid o-ring, cleaned and lubed it. The pump isn't that old and the gasket looked pristine. Turned the pump on and it primed quickly and showed no obvious entrainment of air. So, I thought I fixed the problem. However, this morning I inspected the pump and it was full of air. I turned it on, and it primed quickly, again with no evidence of sucking air. My question is: is it normal for the pump to fill with air after it has not been running for several hours? I'm thinking that when the pump is off, air could be coming back from the pressure side, but I don't know. The only gasket I didn't service was the union gasket where the PVC attaches to the pump.