Low start-up pressure

[Pool in Carolina Blue]

All I know about DE filters is what I have learned here on the forum and I have a sand filter. My first guess would be a torn or damaged grid or whatever they use. Easiest way to check is to throw some DE powder into the skimmer as usual then watch the return jets. If you see DE coming out then something is damaged. Otherwise, it's probably filtering OK. 3 psi isn't really a big change but it could be an indication that something is wrong if you have a long history of readings.
Al

Thanks Al. Nothing came out the return jets and the grids appear to be okay. I have two years of readings so this drop, while not that significant, is somewhat baffling to me.