I'm in the process of shocking which I have done before. I installed a new gauge this year. It has been showing about 10 PSI but the pressure is going down. When I backwash it returns to 10 PSI. Today when I went to backwash it was 5 and returned to 10??? There are no air bubbles or leaks that I see. The system including the Hayward sand filter are going into their fourth season.
I must be going crazy from the shocking and brushing. Could it be a bad gauge?