I was reading some comments on someone else’s post about low PSI and reasons for it. Sorry I can’t find that post now but I was having the same problem. Low psi and loud racket. Someone mentioned cleaning the pump impeller. I googled how to do that and let me tell you. I had a rock. A stick. A birds nest or something. It was nuts. So I cleaned it out and restarted the pump. Holy cow! My psi shot up from like 5 to twelve and now it’s running like it was new. I was fixin to buy a new pump cause I just thought this one was shot. So thanks mystery people!