My sand filter has had odd behavior that I wondered if anyone else has seen.
The gauge goes to zero when off and is around 10psi when the pump is on and the sand is clean. If I run my suction side Kreepy Krauley after not having cleaned the pool for a week or so (there's small leaves on the bottom and maybe some unseen fine silt or dirt down there) after a few hours the gauge gradually climbs to around 15 and the Kreepy Krauley slows somewhat. So far, that's perfectly normal behavior for my equipment and I would then normally perform a backwash. However, if I don't backwash and instead, just shut off the pump and then turn it back on, the filter pressure after that quick Off/On cycle is back to a 10psi reading and the Kreepy Krauley has picked up its pace indicating the change in pressure was real. I do not see any dirt plumes coming from the returns which might be an indicator of something amiss.
So basically I'm loosing back pressure that's developed by a partially clogged filter by simply shutting the filter off and turning it back on. In one sense it's great because I don't waste water backwashing, but obviously something isn't right.
Water is very clear and numbers using TF100 are:
Edit: This behavior has been a happening anytime I notice the filter is starting to clog. Turning the pump Off, and then On "cleans" the filter.