I've had several issues with my pool this spring (busted pipes, busted motor casing, broken filter valve), but now I don't have pressure in my sand filter. I have backwashed it and drained it, but it still isn't working. Any ideas of what I need to do? Thanks!
Always remember to check the obvious things before the complicated ones. Low pressure is most commonly a blockage in the skimmer, pump strainer basket, or pump impeller. Any serious blockage on the intake side will cause a pressure drop. It also pays to double check valve positions. It is possible to get all skimmers and the main drain turned off, or partly off, at the same time. I have spent an hour trying to figure this kind of thing out without noticing that the main drain was off and the skimmer was full of leaves.
Low pressure can also be caused by leaks on the pressure side, but those are usually very very obvious (large quantities of water coming out in the wrong place).
You may not need to replace the gauge. Try removing it an cleaning out the hole in the bottom. Because the gauge is before filtering, they sometimes will get clogged.
Second, I took your original post to mean your pressure reading was near 0 PSI which would be impossible if you had any flow at all and would indicate a problem with your gauge. However, if your return flow is significantly lower than before, and your pressure gauge reads equally lower (but not 0), it could indeed be suction side blockage and worthwhile to check out.
Most of the posts I have seen on other forums regarding low PSI have turned out to be a problem with the gauge.