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POOLS & SPAS · INDEPENDENT IDENTIFICATION GUIDE

How to measure a pool or spa filter cartridge

The diameter and length are only two dimensions. Top and bottom opening geometry, gaskets, closed ends, handles, and the filter housing model can distinguish cartridges that appear nearly identical.

Cartridge catalogs contain very similar sizes with radically different end caps. The useful starting point is the filter housing label and any printed cartridge reference. If these are missing, build a measurement record of the entire old element and its ends. A measurement is evidence for identification, not a verified compatible part.

What this page can establish

A traceable identification record and the next check to make. It does not automatically identify a compatible replacement or certify a product for your equipment.

START HERE

How to work through this specific filter problem

  1. 01

    Find the housing identity

    Identify the manufacturer and full model on the filter tank without opening anything. Read any accessible service documentation first.

  2. 02

    De-energize and depressurize safely

    Only if you are qualified and following the specific manufacturer's procedure, prevent pump restart and confirm all pressure is relieved before opening the vessel.

  3. 03

    Record every end of the cartridge

    Where a safely removed cartridge is available, record outside diameter, full length, top and bottom hole diameter and endcap profile separately.

  4. 04

    Verify application rather than shape

    Compare against the manufacturer's documented cartridge and housing relationship, including seals, number of elements and flow requirements.

WHEN THE SIMPLE ANSWER ISN'T ENOUGH

Choose the situation you actually have

Same length, different top

A handle, molded gasket or closed end changes the physical interface; do not assume interchangeability.

Part number has worn off

Photograph legible labels and describe both ends. Measurements can narrow questions for the maker but never certify a match.

Tank is under pressure

Stop. Depressurization and correct lid/clamp assembly are safety-critical, not ordinary filter-size work.

Common identification mistakes to avoid

  • Measuring only the pleated fabric and excluding molded endcaps.
  • Using a marketplace cross-reference as the only fit evidence.
  • Disassembling a vessel before isolating pump automation and fully relieving pressure.

Safety and accuracy limit

A pool filter vessel can retain dangerous pressure. Do not open clamps or lids or remove any component unless you can follow that exact manufacturer's shutdown, isolation and depressurization procedure. If uncertain, use a qualified pool professional.

YOUR IDENTIFICATION RECORD

Record the clues you actually have

Keep unknown fields empty. This worksheet works entirely in your browser tab; your observations are not uploaded or stored. It helps you ask the right question of the manufacturer, not manufacture a compatibility claim.

TRACEABLE PRIMARY SOURCES

Check the underlying manufacturer or public authority

Reviewed November 5, 2026. These official sources support the identification principles on this page. They do not certify a specific replacement for a device you have not identified.

For a different equipment problem, start with the category directory rather than a guessed replacement.

FilterFound is independent of the listed manufacturers. Product compatibility must be independently confirmed using the complete model and the maker's documentation; no affiliate recommendation is made on this guide.