I fill the pump basket with water and once it turns on water goes away and basket does not fill..my seals all seem tight..impellar rotates by hand..change the sand in filter..filter is Hayward s200..pump is a year old Rx Clear..ran a drain king in skimmer and in pump basket..water seems to flow ok from skimmer to pump basket..I am stumped..worked fine cpl days ago..multi port valve does need replacing..leaks..all other o rings just replaced this yesr..