Strong Spas spa filter (4CH-925)

Strong Industries (catalogs name Antigua / Futura; Strong's FAQ does not)

Replacement numbers

Unicel 4CH-925, Pleatco PSANT20P3

Fits Strong Industries (catalogs name Antigua / Futura; Strong's FAQ does not).

Diameter 4-5/8" (117 mm)Length 7-1/4" (184 mm)20 sq ft1 model listed

Disclosure: we may earn a commission from qualifying purchases made through retailer links on this site, at no extra cost to you. As an Amazon Associate I earn from qualifying purchases. Search on Amazon opens an Amazon search for this part number, not one listing we pre-checked. These are affiliate links. Product photos are omitted unless Amazon supplied one through the Product Advertising API or a SiteStripe image link. Verify dimensions before ordering. Each “Check price on Amazon” button opens a specific listing whose title we checked. The line under the name repeats only that title. See our affiliate disclosure.

Unicel4CH-925
PleatcoPSANT20P3 (Spec table PDF p.31: PSANT20P3, 4-3/4" x 7-1/16", handle, 1-1/2" SAE, 3 oz, 20 sq ft, Futura Spa (Strong Industries). PSANT20P4 is the same size with 1-1/2" MPT. Application index PDF p.27: Strong Antigua.)
FilburFC-0126
Topsemi-circular handle
Bottom1-1/2" SAE
Ø 4-5/8" (117 mm)7-1/4" (184 mm)Side view · end views belowTopBottom
Top: semi-circular handle
Bottom: 1-1/2" SAE
Drawn to scale from the listed diameter and length. Handles, threads and closed ends are drawn as symbols, not to scale. 20 sq ft media.

Request a filter replacement reminder

This stores a request for this filter: the model, the date you installed it, and how often you replace it. Submitting stores the request and does not send email.

We'll only use your email for this request.

Deletion requests go only to the address on the privacy page.

Strong Industries (catalogs name Antigua / Futura; Strong's FAQ does not) is the group name on the Strong Spas row 4CH-925 cartridge (Antigua / Futura). Match these numbers: Unicel 4CH-925; Pleatco PSANT20P3; Filbur FC-0126. 4-5/8" across, 7-1/4" long, top semi-circular handle, bottom 1-1/2" SAE, 20 sq ft.

Catalog note for PSANT20P3: The 20 sq ft Strong cartridge in the catalogs, shown at Unicel's size. Pleatco lists PSANT20P3 for Futura Spa (Strong Industries) at 4-3/4" x 7-1/16", and its application index says Strong Antigua, 1.50" SAE. Filbur's Strong section spells the model Antiqua and prints FC-0126 at 4-3/4" x 8", with the Unicel cell blank; a separate Filbur size table crosses FC-0126 to 4CH-925. Strong's FAQ does not mention this cartridge. Pleatco and Filbur also list an MPT version (PSANT20P4 / FC-0208) that is not 4CH-925.

4CH-925 (OEM 4CH-925 cartridge (Antigua / Futura)), Pleatco side: Spec table PDF p.31: PSANT20P3, 4-3/4" x 7-1/16", handle, 1-1/2" SAE, 3 oz, 20 sq ft, Futura Spa (Strong Industries). PSANT20P4 is the same size with 1-1/2" MPT. Application index PDF p.27: Strong Antigua..

PSANT20P3, Filbur note: Strong Industries section, PDF p.26 (printed p.51): FC-0126, 4-3/4" x 8", handle, 1-1/2" SAE, Antiqua, Pleatco PSANT20 / PSANT20P3, Unicel cell N/A, 20 sq ft. Size table PDF p.9 crosses FC-0126 to 4CH-925. FC-0208 is the 7-1/16" MPT Futura cartridge..

Hot tubs named for PSANT20P3: Strong Antigua / Futura Spa, no year range printed, listed by Pleatco 2023 Catalog (20 sq ft, 1-1/2" SAE; Pleatco says Antigua, Filbur says Antiqua; not in Strong's FAQ).

Left blank on purpose: Length disagrees: Unicel 7-1/4", Pleatco 7-1/16", Filbur FC-0126 8". Outside diameter 4-5/8" (Unicel) vs 4-3/4" (Pleatco, Filbur). No Strong OEM number. Not the 50 or 75 sq ft filter in Strong's series FAQ..

Where those figures are printed: Unicel 2026 Replacement Guide on 4CH-925 (Strong Industries section, PDF p.58 (printed p.54): 4CH-925, 4-5/8" x 7-1/4", 1-1/2" SAE, 20 sq ft, 3 oz, no model name; spec table PDF p.7 (printed p.3): 190 pleats, semi-circular handle). Pleatco 2023 Catalog on 4CH-925 (Spec table PDF p.31: PSANT20P3 for Futura Spa (Strong Industries), 4-3/4" x 7-1/16", 1-1/2" SAE, 20 sq ft; application index PDF p.27: Strong Antigua). Filbur Catalog & Reference Guide on 4CH-925 (Strong Industries, PDF p.26 (printed p.51): FC-0126, 4-3/4" x 8", Antiqua, Unicel N/A; size table PDF p.9: FC-0126 = 4CH-925 = PSANT20P3). Strong Spas (manufacturer FAQ) on 4CH-925 (What size filter does my spa use?: 50 or 75 sq ft by series and year, no part number, and no mention of Antigua, Futura or a 20 sq ft cartridge).

Hot tubs listed for this cartridge

The rest of the Strong Spas model list is the Strong Spas filter by model and year lookup.

Model / systemYearsListed by
Strong Antigua / Futura Spa (20 sq ft, 1-1/2" SAE; Pleatco says Antigua, Filbur says Antiqua; not in Strong's FAQ)not givenPleatco 2023 Catalog

Check the cartridge you removed

Measure diameter, length, and both ends, then compare them with the figures above. The steps are in the measuring guide. Why the bottom decides whether it seals: open-end vs threaded filters. Power, the retainer, and not running the spa empty: how to install a cartridge. Number formats: how Filbur, Unicel and Pleatco numbers compare.

Every number on this row, on one screen: cross-reference lookup. Published clean and replace intervals for this cartridge, and a buy link for the numbers above: replacement schedule and reorder. The interval comparison by brand: calculator.

Cleaner and test strips

Hose rinse and soak steps are in how to clean a cartridge. Named cleaners and strips are in filter cleaners and test strips.

Filter cleaner and test strips

Sources

Not in sources: Length disagrees: Unicel 7-1/4", Pleatco 7-1/16", Filbur FC-0126 8". Outside diameter 4-5/8" (Unicel) vs 4-3/4" (Pleatco, Filbur). No Strong OEM number. Not the 50 or 75 sq ft filter in Strong's series FAQ..