Hi all!! We have an in ground pool with a sand filter pump. This year after opening we are having a problem with the pump and don’t know where to start looking to correct the issue. Sand was replaced last year. Checked the O ring and there is no visible crack. The pump is having trouble priming and when we run the vacuum it isn’t sucking like it should. Pressure is reading normal at this point. The return jets are sputtering. There is sufficient water in the pool. Any advice would be so helpful! Thank you!