i opened my pool friday night and the pump/filter were going since friday till this morning. the pressure with freshly coated filter was 9. over the course of 2 days it gradually built up to 11 psi (not much junk in the pool.)
i scheduled the pump to run on the clock and today i noticed that the filter pressure was 9 psi. the jets are working fine, skimmer sucks fine. there are no bubbles in the pump basket, no air in the return.
the only difference from this morning was that i buried some pipework i did a week ago. the pipework was all open and running fine for 2 days with no leaks. there are no apparent signs of any leak - the ground is dry, the water level stayed put. i think if the pressure drop was due to a leak i would see some air in the return and the water loss should be significant to drop 2 psi.
only think i can think of is some settlement of the DE in the filter and i should simply keep an eye on the pressure to make sure it's going up. no sign of DE in the water. the water looks good.
is there anything that can contribute to this sudden drop? anything i should worry about?