Pool & Spa Filter Cartridges: Sizing Guide & Replacements
Pool and spa filters are the frontline defense against algae, bacteria, and debris in your water. A worn cartridge filter allows fine particles to pass through, turning clear water cloudy and increasing chemical consumption. Proper sizing and timely replacement keep your pool sparkling and reduce the need for shock treatments.
Intex
Pleatco
How to Size and Select Pool Filter Cartridges
Pool filter cartridges are measured by three critical dimensions: outer diameter, inner diameter, and length. Even a half-inch discrepancy in any measurement will cause water bypass — unfiltered water flowing around the cartridge rather than through it. Always measure your existing cartridge or reference the filter housing model number.
The square footage rating of your filter cartridge must match or exceed your pool's volume. For residential pools up to 15,000 gallons, a 100-200 sq ft cartridge is standard. For pools up to 30,000 gallons, look for 200-400 sq ft ratings. Undersizing your filter leads to rapid clogging and poor circulation.
Cartridge fit is set by the pleat area, the cartridge diameter and the end-cap type. Check those against your housing — the model number printed on the old cartridge is the fastest route. Listings differ in what they publish about media and tolerances, and we do not verify those claims.
Frequently asked
01How do I know when to replace vs. clean my pool filter?
02Can I use a larger filter cartridge than my original?
03Do I need to soak new cartridges before use?
The Magnuson-Moss Warranty Act (15 U.S.C. 2301-2312) prohibits manufacturers from voiding your warranty solely for using third-party replacement parts.Read more