my stupid pool pump keeps getting air bubbles in the output tube. ive tightened the hose clamps, checked the gasket aroud the pressure relief valve on the lid. its a little intech 1000. gallon per hour paper filter pump. it runs 24 hrs a day, had it over 2 years. is the pump failling? if it is, should i buy a larger pump? i have a 15ft x 4ft 5000 gallon pool