DE Filter
A DE (diatomaceous earth) filter uses diatomaceous earth powder coated on internal grids to filter pool water to 3–5 micron fineness.
Definition
A DE (diatomaceous earth) filter uses diatomaceous earth powder coated on internal grids to filter pool water to 3–5 micron fineness.
Typical Values: Filtration fineness: 3–5 microns; Recharge with DE after backwashing
In Plain Language
DE filters consist of a housing with fabric-covered grids. Diatomaceous earth (the fossilized shells of diatoms) is added and coats the grids, creating a very fine filtration surface. Water passes through this DE layer, which captures particles down to 3–5 microns — finer than either sand or cartridge filters. DE filters require periodic backwashing, adding fresh DE powder, and annual disassembly for full cleaning.
Why It Matters
DE filters produce the clearest water of any standard pool filter type but require more maintenance knowledge and attention than sand or cartridge.
Typical Values
Filtration fineness: 3–5 microns; Recharge with DE after backwashing
Last reviewed: 2026-06-01