Freeflow Spas spa filter (4CH-22)

Freeflow Spas

Replacement numbers

Unicel 4CH-22, Pleatco PFF25W-P4

Fits Freeflow Spas.

Diameter 4-15/16" (125 mm)Length 6-5/8" (168 mm)25 sq ft2 models listed

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Unicel4CH-22
PleatcoPFF25W-P4 (Unicel cross-reference PDF p.47: 4CH-22 = PFF25W-P4. Spec table PDF p.32: PFF25W-P4 is 5" x 6-5/8", open 2-1/8", 1-1/2" MPT, 25 sq ft, Freeflow Lagas. Spec table PDF p.31: PFF25P4 is the 4-5/8" open cartridge for Lagas, CLX, FF-150. Filbur, not Pleatco's cross-reference, ties PFF25P4 to 4CH-22.)
FilburFC-2399
Top2-1/8" (54 mm) / open
Bottom1-1/2” male thread/MPT
Ø 4-15/16" (125 mm)6-5/8" (168 mm)Side view · end views belowTopBottom
Top: 2-1/8" (54 mm) / open
Bottom: 1-1/2” male thread/MPT
Drawn to scale from the listed diameter and length and open-end sizes. Handles, threads and closed ends are drawn as symbols, not to scale. 25 sq ft media.

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Freeflow Spas files this cartridge as 4CH-22 cartridge (open top), in the Freeflow Spas group. Numbers on the row: Unicel 4CH-22; Pleatco PFF25W-P4; Filbur FC-2399. 4-15/16" across, 6-5/8" long, top 2-1/8" / open, bottom 1-1/2” male thread/MPT, 25 sq ft.

PFF25W-P4 carries this note from the catalogs: Unicel's spec table and Freeflow model list assign the open-top 4CH-22 to TLX and RLX: 4-15/16" x 6-5/8", 212 pleats, 3 oz, 25 sq ft, 1-1/2" MPT. Filbur's size table and its Freedom Spas section assign that same open 4CH-22 / FC-2399 to CLX (and FF-150) and print Pleatco PFF25P4. Pleatco's own Unicel cross-reference prints 4CH-22 = PFF25W-P4, which Pleatco sizes at 5" x 6-5/8" for Lagas and does not name TLX, RLX or CLX. The dimension on this row is Unicel's.

4CH-22 (OEM 4CH-22 cartridge (open top)), Pleatco side: Unicel cross-reference PDF p.47: 4CH-22 = PFF25W-P4. Spec table PDF p.32: PFF25W-P4 is 5" x 6-5/8", open 2-1/8", 1-1/2" MPT, 25 sq ft, Freeflow Lagas. Spec table PDF p.31: PFF25P4 is the 4-5/8" open cartridge for Lagas, CLX, FF-150. Filbur, not Pleatco's cross-reference, ties PFF25P4 to 4CH-22..

PFF25W-P4, Filbur note: Dimensional listing PDF p.9: FC-2399, 4-15/16" x 6-5/8", open 2-1/8", 1-1/2" MPT, Freeflow 25, CLX, PFF25P4, 4CH-22, 25 sq ft. Freedom Spas section PDF p.18 (printed p.35): CLX, FF-150. Filbur has no Freeflow heading..

Model list attached to 4CH-22 cartridge (open top): Freeflow TLX and RLX, no year range printed, listed by Unicel 2026 Replacement Guide (Unicel spec table and Freeflow model list: open top, 4CH-22); Freeflow CLX, no year range printed, listed by Filbur Catalog & Reference Guide (Filbur FC-2399, open top, also numbered FF-150. Pleatco PFF25P4 names Lagas, CLX and FF-150. This is not Unicel's model assignment.).

4CH-22 is easy to confuse on the Freeflow Spas table. 4CH-23 differs by Unicel 4CH-23, Pleatco PFF25TC-P4, Filbur FC-2400, top closed, note says Unicel's spec table assigns the closed-top 4CH-23 to Freeflow CLX: 4-15/16" x 6-5/8", 212 pleats, 3 oz, 25 sq ft, 1-1/2" MPT. The Freeflow model list agrees. Filbur and Pleatco agree that 4CH-23 / FC-2400 / PFF25TC-P4 is the closed cartridge, and they assign it to TLX and RLX instead of CLX. Pleatco also names Lagas, FF-100 and Claro. Pleatco's outside diameter is 4-5/8".. 5CH-45 differs by Unicel 5CH-45, Pleatco PFF50P4, Filbur FC-2401, 5-5/16" diameter, 10" long, 45 sq ft, note says Unicel's spec table prints 5CH-45 for Freeflow Legend: 5-5/16" x 10", open 2-1/8", 1-1/2" MPT, 225 pleats, 3 oz, 45 sq ft. The Freeflow model list puts Legend and Passport on that row. Passport is not in the spec-table model cell, and Filbur and Pleatco do not name Passport. Pleatco PFF50P4 is 50 sq ft. Filbur's size table is 5-5/16" and 45 sq ft with Pleatco cell PFF50P; Filbur's Freedom Spas section prints the diameter as 5-1/4"..

Left blank on purpose: Model names are swapped: Unicel says TLX/RLX, Filbur and Pleatco's PFF25P4 say CLX. Pleatco equivalent is not one number (PFF25W-P4 on the cross-reference, PFF25P4 in Filbur). Outside diameter 4-15/16" (Unicel, Filbur) vs 4-5/8" (PFF25P4) vs 5" (PFF25W-P4). No Freeflow OEM number in Unicel. FF-150 is Filbur/Pleatco only, so it is not an OEM lookup number..

Source locations for this Freeflow Spas row: Unicel 2026 Replacement Guide on 4CH-22 (Freeflow model list, PDF p.35 (printed p.31): TLX and RLX = 4CH-22; spec table PDF p.8 (printed p.4): open 2-1/8", 212 pleats, 3 oz, 25 sq ft, model cell TLX, RLX). Pleatco 2023 Catalog on 4CH-22 (Unicel cross-reference PDF p.47: 4CH-22 = PFF25W-P4. Spec table PDF p.32: PFF25W-P4 at 5" x 6-5/8" for Lagas. Spec table PDF p.31: PFF25P4 at 4-5/8" x 6-5/8" for Lagas, CLX, FF-150). Filbur Catalog & Reference Guide on 4CH-22 (Dimensional listing PDF p.9: FC-2399 open, CLX, PFF25P4, 4CH-22. Freedom Spas section PDF p.18 (printed p.35): CLX, FF-150).

Hot tubs listed for this cartridge

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

Model / systemYearsListed by
Freeflow TLX and RLX (Unicel spec table and Freeflow model list: open top, 4CH-22)not givenUnicel 2026 Replacement Guide
Freeflow CLX (Filbur FC-2399, open top, also numbered FF-150. Pleatco PFF25P4 names Lagas, CLX and FF-150. This is not Unicel's model assignment.)not givenFilbur Catalog & Reference Guide

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.

Other Freeflow Spas cartridges

All 3 Freeflow Spas spa filters

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: Model names are swapped: Unicel says TLX/RLX, Filbur and Pleatco's PFF25P4 say CLX. Pleatco equivalent is not one number (PFF25W-P4 on the cross-reference, PFF25P4 in Filbur). Outside diameter 4-15/16" (Unicel, Filbur) vs 4-5/8" (PFF25P4) vs 5" (PFF25W-P4). No Freeflow OEM number in Unicel. FF-150 is Filbur/Pleatco only, so it is not an OEM lookup number..