Listing we opened and checked. Match the diameter, length and both fittings on this page before you order. The price is on Amazon; we do not print one.
Cal Spas OEM FIL11100303 spa filter (4CH-252)
Cal Spas
Replacement numbers
Unicel 4CH-252, Pleatco PMA20-F2M
Fits Cal Spas OEM FIL11100303.
Diameter 4-5/8" (117 mm)Length 8" (203 mm)25 sq ftPleatco PMA20-F2M
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| Unicel | 4CH-252 |
|---|---|
| Pleatco | PMA20-F2M |
| Filbur | not found in Filbur catalog |
| Top | molded cone handle |
| Bottom | 2” male thread/MPT |
Bottom: 2” male thread/MPT
Drawn to scale from the listed diameter and length. Handles, threads and closed ends are drawn as symbols, not to scale. 25 sq ft media.
For Cal Spas, 4CH-252 cartridge (OEM FIL11100303) sits in Cal Spas. The cross-reference prints OEM FIL11100303; Unicel 4CH-252; Pleatco PMA20-F2M. 4-5/8" across, 8" long, top molded cone handle, bottom 2” male thread/MPT, 25 sq ft.
FIL11100303 carries this note from the catalogs: Unicel: Cal Spa original has 4-3/4" OD.
Before ordering 4CH-252, compare it with 4CH-19 differs by Unicel 4CH-19, Pleatco PSG13.5P4, Filbur FC-0122, 4-5/8" long, bottom 1-1/2” male thread/MPT, 13 sq ft, OEM FIL11100305, note says Unicel: verify thread diameter; and 5CH-502 differs by Unicel 5CH-502, Pleatco PPM50SC-F2M, Filbur FC-0195, 5-3/16" diameter, 12-1/2" long, top bar handle, 50 sq ft, OEM FIL11100202, note says Unicel prints OEM FIL11100202 on its own line between 5CH-502 and 5CH-752. Two Cal Spas parts retailers resolve it: Hot Tub Outpost lists Cal Spas FIL11100202 as a 50 sq ft cartridge, 12-1/2" long with a handle top and 2" MPT bottom, that replaces FIL11100200 and FIL11100201 and crosses to Unicel 5CH-502 and Pleatco PPM50SC-F2M; Wizard of Spas lists FIL11100202 (and FIL11100201) as the Cal Spas 50 sq ft cartridge with Filbur FC-0195M. Hot Tub Outpost prints the diameter as 5-1/8" (Unicel and Filbur: 5-3/16") and gives the Filbur number as FC-0196, which the Filbur catalog assigns to the 35 sq ft 5CH-352; the Filbur match shown here is the catalog's own FC-0195..
Filbur does not have a number on this row. Search FIL11100303 or the Cal Spas part you pulled out of the spa.
Left blank on purpose: no Filbur equivalent found in Filbur catalog; no model/model-year fitment in sources.
Where those figures are printed: Unicel 2026 Replacement Guide on 4CH-252 (OEM cross reference (Cal Spas section), PDF p.30 (printed p.26); spec table PDF p.7 (printed p.3)). Pleatco 2023 Catalog on 4CH-252 (Unicel-to-Pleatco cross reference, PDF p.47).
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.
The same 4CH-252 number is also on the Master Spas, Coleman Spas pages.
Other Cal Spas cartridges
- 4CH-19 cartridge (OEM FIL11100305), 4-5/8" (117 mm) × 4-5/8" (117 mm)
- 5CH-502 cartridge (OEM FIL11100202), 5-3/16" (132 mm) × 12-1/2" (318 mm)
- C-5374 cartridge, 5-5/16" (135 mm) × 14-13/16" (376 mm)
- 5CH-752 cartridge, 5-3/16" (132 mm) × 16-1/8" (410 mm)
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
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Leisure Time O Filter Clean Cartridge Cleaner Listing title: cartridge cleaner, 32 fl oz.
-
SpaGuard Filter Cleaner Listing title: filter cleaner for spas and hot tubs, 1 quart.
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AquaChek SPA 6-in-1 Test Strips Listing title: reads total bromine, total chlorine, free chlorine, pH, total alkalinity and total hardness.
Pleatco PMA20-F2M Listing we opened and checked. Match the diameter, length and both fittings on this page before you order. The price is on Amazon; we do not print one.
Sources
- Unicel 2026 Replacement Guide: OEM cross reference (Cal Spas section), PDF p.30 (printed p.26); spec table PDF p.7 (printed p.3) (PDF)
- Pleatco 2023 Catalog: Unicel-to-Pleatco cross reference, PDF p.47 (PDF)
Not in sources: no Filbur equivalent found in Filbur catalog; no model/model-year fitment in sources.