Good morning TFP.
I have a hayward sand filter for my salt water pool. Recently i've noticed quite a few things going on. ( Please keep in mind this pool is only on it's 3rd summer). First i noticed that the pressure gauge wasn't working, so i replaced it. Then i noticed that the valve handle was very giggly even after setting it in backwash or filter, so i took it in, had the seals inspected (good) and had the spring replaced.
i got home put the filter top back on and it still is not working properly. The last thing i noticed is that even in filter mode, there sound like air is going through yup checked for leaks). I also noticed that the backwash leaks a little even when on filter mode. Last but not least... on backwash mode, absolutely nothing goes through the sight glass bottle. Please help if you can, i'm beyond frustrated.