My UV pressure gage reads low. It goes to 0 pressure quickly even after a recent filter clean. Sometimes in less than a day. We have cleaned the filter at least 5 times this year (sometimes a good rinse and sometimes chemically cleaned) and pressure readings on the UV pump start at 10 and deteriorate quickly. Pressure reduces to 0 within a day or two and then there is not enough pressure for UV to work or to get the heat pump to work. I also can never run the heat pump at the same time as the shark as there is never enough pressure to do both so we tend to take the shark out during day time and run the heat pump only in the day. The pressure in the filter seems fine. Something changes when it goes to the UV. Any suggestions?