Skip to main content
Pool Filter Guide

Complete Guide · 11 articles

DE Pool Filter Guide — How They Work, How to Maintain Them

DE (diatomaceous earth) filters provide the finest filtration available for residential pools — down to 2–5 microns vs 20–40 microns for sand. They require more maintenance than sand or cartridge filters, but the water clarity is unmatched. This guide covers everything from how DE filters work to grid cleaning, DE powder quantities, and troubleshooting.

Pool Filter Guide Editorial Team 4 FAQs answered Updated 2025-04-14

All Guides in This Section

11 articles
Guide 01

What Is a DE Pool Filter?

How diatomaceous earth filters work and why they filter finest.

Read guide
How-To 02

How to Backwash a DE Filter

DE backwash is different - you must re-add DE powder after every backwash.

Read guide
How-To 03

How Much DE for Pool Filter?

DE powder quantity by filter size - and how to add it correctly.

Read guide
How-To 04

How to Clean a DE Pool Filter

Backwash routine plus full annual grid service - the step most owners skip.

Read guide
How-To 05

DE Pool Filter Grids

How to clean, inspect, and replace DE filter grids.

Read guide
Review 06

Best DE Pool Filter

Pentair FNS Plus vs Hayward Pro-Grid - DE filters ranked on clarity, maintenance burden, and build quality.

Read guide
Comparison 07

DE vs Sand vs Cartridge Filter

Side-by-side comparison: filtration quality, cost, maintenance.

Read guide
How-To 08

How to Add DE to a Pool Filter

Step-by-step: initial charge and post-backwash recharge with DE powder dosage by filter size.

Read guide
Guide 09

DE Filter for an Above-Ground Pool

Whether a DE filter suits an above-ground pool, and the small units that fit.

Read guide
Guide 10

How Often to Clean a DE Filter

Bump, backwash, and full teardown intervals based on filter pressure.

Read guide
Guide 11

DE Powder Alternatives

Cellulose fiber and perlite compared to DE: dosing, safety, cost, and what does not work.

Read guide
Check DE Powder Prices

Frequently Asked Questions

What is a DE pool filter?
A DE (diatomaceous earth) pool filter uses a fine powder made from fossilized algae (diatoms) coated on filter grids to trap particles as small as 2–5 microns — the finest filtration of any pool filter type. The DE powder is the actual filtering medium, not the grids themselves. After each backwash, you must add fresh DE powder to re-coat the grids.
How much DE do you add after backwashing?
After backwashing, you replace approximately 80% of the filter's rated DE capacity. A 48 sq ft filter (a common residential size) holds about 6 lbs of DE total, so you would add roughly 4.8 lbs (just under 1 lb per 10 sq ft of filter area). Mix the DE with water in a bucket first to form a slurry, then pour it into the skimmer with the pump running.
How do you clean DE filter grids?
To deep-clean DE filter grids: (1) Backwash the filter. (2) Turn off the pump and release pressure. (3) Remove the filter lid and carefully pull out the grid assembly. (4) Soak the grids in a filter cleaning solution for several hours or overnight. (5) Rinse each grid thoroughly. (6) Inspect for tears — even a pinhole will cause DE to pass into the pool. (7) Reassemble and add fresh DE.
Why is DE powder getting into my pool?
DE in your pool water means DE is bypassing the grids — typically caused by a torn or damaged filter grid. Even a small pinhole allows DE to return through the return jets. To diagnose: backwash, add fresh DE, and watch for cloudy white water coming from the jets. If you see it, disassemble and inspect every grid carefully. Replace any grid with visible damage.

Explore Other Filter Guides

Sand Filters Backwashing Cartridge Filters Maintenance