Swimming Pool Filter Cartridge Replacements

Restore peak filtration to your pool with replacement pool filter cartridges from Filbur and a DE filter grid from Purex. PST Pool Supplies stocks Filbur cartridges in a full range of sizes — 25 to 137 square feet — to match single-cartridge, 2-cartridge, and 4-cartridge filter systems, plus a Purex full 12" DE grid (24 sq ft) for DE filter restoration, starting from $17.90.

Filbur is one of North America's leading aftermarket pool filter cartridge manufacturers, producing Reemay spunbond polyester filter media — a continuous-filament polyester construction with no binders that could limit filter area, providing excellent dirt-holding capacity and consistent filtration down to approximately 10–15 microns. Cartridges are available across the full residential size range: 25 sq ft (4-5/8" × 11-7/8") for compact single-element filters; 40 sq ft castle style (4-5/8" × 16-3/4") for mid-size filters; 75 sq ft cone bottom (7" × 19-5/8") for Hayward and similar filters; 81 sq ft (3" openings, 7" × 19-5/8", available as 4-pack) for 4-cartridge systems requiring the standard 7" diameter; 85 sq ft (3" openings, 9-1/4" × 14-3/16") for wider-diameter single elements; 90 sq ft (4" openings, 8-15/16" × 17-3/8"); 112 sq ft (3" openings, 7" × 25-1/2"); 131 sq ft (3" openings, 7" × 32-7/8"); and 137 sq ft (4-3/16" openings, 8-11/16" × 31-1/4") for large-volume inground filter systems. The Purex full 12" DE grid (24 sq ft) is a complete grid assembly for Purex/Pentair DE filter tanks — for restoring a single failed grid section or full grid set replacement. For individual replacement parts and accessories for filter tanks, see our pool filter parts collection.

Cartridge selection requires matching three key specifications to the existing cartridge or the filter's OEM specifications: filtration area (square footage), overall dimensions (length and outer diameter), and end-cap configuration (open-open, open-closed, or threaded openings and their diameters). A cartridge that fits correctly in the filter housing but has the wrong filtration area will either underfilter (too small) or create excessive back-pressure (too large for the pump's flow range). For 4-cartridge systems (Hayward C4025, Pentair Clean & Clear Plus, and similar), always replace all four cartridges simultaneously — mixing old and new cartridges creates unequal flow distribution that accelerates wear on the new cartridges. Replace cartridges annually under normal residential use; inspect and clean every 4–6 weeks during swim season.

Shop pool filter cartridge replacements at PST Pool Supplies and restore your pool's filtration to like-new performance.