Pool Filter Types Compared: Sand, Cartridge, and DE
The three filter types trade off the same three things differently: filtration fineness, maintenance effort, and upfront/ongoing cost. Unincorporated Harris and Montgomery County lots around Tomball and Magnolia often run on septic and private well systems, so equipment pads, plumbing runs, and excavation are planned around those systems during the site evaluation, not discovered mid-dig.
How Each Type Filters
Sand filters push water through a bed of specially graded sand that traps particles roughly 20-40 microns and larger; they are cleaned by backwashing, which reverses flow to flush trapped debris out to waste.
Cartridge filters use a pleated fabric element that traps particles down to roughly 10-20 microns; they are cleaned by removing the cartridge and hosing it off (or soaking it periodically in a cleaning solution), with no backwash water lost.
DE (diatomaceous earth) filters coat a set of fabric grids with a fine powder made from fossilized diatoms, trapping particles as small as 3-5 microns, the finest filtration of the three; they are also cleaned by backwashing, with fresh DE powder recharged afterward.
Which One Fits Which Situation
Sand filters are the lowest-maintenance and least expensive to operate but offer the coarsest filtration; a reasonable default for a straightforward residential pool without unusual water-clarity demands.
Cartridge filters trade a bit more hands-on cleaning for finer filtration and no backwash water waste, a common upgrade choice. DE filters give the clearest water of the three but need the most attention (periodic DE recharging) and typically cost more to operate; they are most often chosen for pools where water clarity is a priority worth the extra maintenance.
FAQs
How often should a sand filter be backwashed?
When the pressure gauge reads 8-10 psi above the clean, just-backwashed baseline, not on a fixed calendar schedule; backwashing too early wastes water and filter media life.
Does filter type affect how fast chemicals work?
Finer filtration (DE, then cartridge, then sand) removes smaller particles that can shade or interfere with chlorine's effectiveness, so finer filtration can modestly help water clarity and sanitizer efficiency, though chemistry still does the sanitizing work.
Where This Fits
See our Pool Repair service page, or Financing if cost is the next question.
Related Reading
DIY Pool Leak Detection Basics
How to tell normal evaporation from an actual leak, and when it is time to call for a professional leak check.
Understanding Pool Pump Sizing and Horsepower
Why a bigger pump isn't automatically better, and how pump size actually gets matched to a pool.
Salt Cell Cleaning and Replacement
How to tell when a salt chlorine generator cell needs cleaning versus full replacement.
Get a Free Quote
Tell us about your project and we’ll follow up within one business day.