I first noticed a few days ago after I backwashed that sand would come out of the returns for 5-10 seconds.. I then read in pool school about rinsing before going back to filter. I backwashed, then rinsed for 15 seconds then went to filter and there was no sand. Yesterday I just turned the pump off to un-hook my polaris and turned the pump back on and there went sand for a few seconds. I've been told it might be a broken lateral. I've read something about a spider gasket needing replaced. Does anyone know why it would be doing this?