4-5/8" × 7-1/4"
Strong Spas spa filters
Strong’s own FAQ gives filter area by series and year, and no part number: 50 sq ft for Vienna 60, Madrid 60, Embark, G-2, and Summit or Ascent models built in 2023 or later, and 75 sq ft for Summit and Ascent models built in 2022 or earlier.
The cartridge Unicel, Pleatco and Filbur list for Strong is a different 20 sq ft SAE filter for the Antigua / Futura (4CH-925 / PSANT20P3 / FC-0126), and the three catalogs disagree on its length. That conflict, and why the FAQ’s 50 sq ft filter is not identified as Unicel C-4950, is on the Strong Spas filter page.
This page lists 1 Strong Spas replacement cartridge from the Unicel 2026 Replacement Guide, the Pleatco 2023 catalog, the Filbur catalog and manufacturer and retailer pages, plus model and model-year fitment for 1 of them (1 hot tub models in total). 1 has a Filbur number. Find your spa filter by the OEM part number on the end cap, or measure it and compare sizes below.
Clean and replace intervals for one cartridge on this list, plus the cross-reference numbers and a buy link: filter replacement schedule and reorder.
| Cartridge | Unicel | Pleatco | Filbur | Size | Fits | Status |
|---|---|---|---|---|---|---|
| 4CH-925 (Strong Industries (catalogs name Antigua / Futura; Strong's FAQ does not)) | 4CH-925 | PSANT20P3 | FC-0126 | 4-5/8" (117 mm) × 7-1/4" (184 mm), 20 sq ft | 1 model | verified |
Know your model but not the part number? See Strong Spas filter by model and year.
Guides that apply to Strong Spas
- Open-end vs threaded hot tub filters
- How Filbur, Unicel and Pleatco numbers compare
- How to find your spa filter size
- How to install a cartridge
- All guides
Search Strong Spas part numbers on Amazon
Each button opens an Amazon search for that part number. The cartridge page is where the cited size and fittings are. Match those before you buy.
Part numbers from this table
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4CH-925 cartridge (Antigua / Futura)
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Model-year fitment comes only from the sources named on each cartridge page. Where no source lists models or years, the page says so.