Pool filter - when it is off, preassure still stays

Hi,
I bought a house with pool and have a question: My pool sand filter just after backwash shows about 15psi and even running two weeks without backwashing still stays at about the same level. Is 15psi not too high for clean sand filter? Other people here talked about 10-12psi. Also, when I turn off my pump for a night, sometimes filter preassure goes down to 0, but sometimes it stays at exactly the same level as it was with pump on - about 15psi. Is that normal?
Thank you very much for your help.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
That doesn't sound normal, to me. Have you ever seen it at any reading other than 0 or 15psi? Have you noticed any difference when you backwash? It might be best to just replace the gauge, since you say sometimes when you turn it off the reading doesn't change, and sometimes it goes to 0. My 10-y/o Hayward gauge frequently needed the Flick Test, but other than that it was pretty accurate so I never saw any real need to replace it. Another thing you might try is to check that nothing's impeding the return flow. Do you have any add-ons, like chlorinators? Coudl also try unscrewing the deflectors from the return outlets, allowing free flow and then see if you then get a different reading. I've found dead mice in my lines before... :-()

15psi
10-12psi.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.