Check valves were removed by the PB shortly after the build to troubleshoot a flow problem. (There may have only been one at the return end pipe.) Even though they were not the culprit, they were never reinstalled. Each morning, when my pump starts, I get a large bubble from the return nearest the pump. It's large enough to push water over on to the deck. I asked my PB at the time and was told this was okay and the check valves weren't necessary since I did not have a heater or SWG. I manually chlorinate. I suspect air backflows through the Ozone relief valve when the pump is off. I plan on a switch to salt when that dies. Should I be concerned about the bubble creating stress on the PVC pipes? Should I install check valves anyway?
