DE Filters - How often do they need to be cleaned?

[Mariza]

I need some info on the DE filter. I know for the sand filters, you
need to replace the sand inside the filter every so often. How does it work
with a DE filter?

[MaryLee]

As soon as the pressure rises 10 psi from its original starting pressure, then it's time to backwash.

Edited to add: The difference is that with a DE filter after you backwash, you need to recoat the grids with DE....this involves putting the recommended amount of DE for your size filter into the skimmer and letting it recoat. I believe with sand filters you can leave the sand in it for years and years before it needs to be replaced (if at all).