Discount Pool Filters — Cartridges & DE Grids for Inground & Above Ground Pools

Replace your pool's filter cartridges and DE grids at discounted prices with high-quality Filbur replacement filters for inground and above-ground pools. PST Pool Supplies stocks a comprehensive range of replacement pool filter cartridges in sizes from 75 to 137 square feet, plus Purex DE grids, covering the most common filter configurations at prices starting from $18.

Filbur replacement filter cartridges are manufactured to OEM specifications and are direct replacements for Hayward, Pentair, Jandy, Waterway, and other major filter brands. The collection spans the most common cartridge sizes: 75 sqft (cone bottom, 7", 19-5/8"), 81 sqft (3" open top/bottom, 7", 19-5/8"), 85 sqft (3" open top/bottom, 9-1/4", 14-3/16"), 90 sqft (4" open top/bottom, 8-15/16", 17-3/8"), 112 sqft (3" open top/bottom, 7", 25-1/2"), 131 sqft (3" open top/bottom, 7", 32-7/8"), and 137 sqft (4-3/16" open top/bottom, 8-11/16", 31-1/4"). Multi-pack sets (4 pack) are available for the most popular sizes, offering significant savings over single-cartridge purchases — ideal for filters requiring multiple cartridges per element assembly. The Purex DE grid for 24 sqft (full, 12") completes the selection for DE filter owners. For branded filter hardware and complete filter systems, browse our DE filter collection and our filter parts collection. Filter sizing and replacement guidance is available at Hayward's filter support page and Pentair's filter resource center.

Cartridge filter replacement is one of the most impactful maintenance tasks for pool clarity and water quality. A clogged or worn cartridge forces your pump to work harder against elevated backpressure, reducing flow through the filter and leaving finer particles in the water. Cartridges should be cleaned (pressure rinsed with a garden hose) every 4–6 weeks during active season and replaced when they no longer clean up adequately after rinsing, show visible tears or delamination, or when the filter runs at consistently elevated pressure despite being clean. Matching your replacement cartridge's exact dimensions (length, end fitting outer diameter, and surface area) is critical — an incorrect cartridge won't seal properly in the filter housing and will allow unfiltered water to bypass. The measurements provided in each product name (OT = open top, OB = open bottom diameter; length in inches) are used to cross-reference to OEM part numbers.

Shop discount pool filter cartridges and DE grids and restore your pool's filtration to peak performance at reduced cost.