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. Lakefront lots near Lake Conroe need grading and drainage planned so the pool, the slope to the water, and any retaining structure all work together, which is covered in the site evaluation before anything is designed.
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.
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