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.
4CH-20 spa filter equivalents
Part number 4CH-20 appears in 3 cross-reference rows below. Each row lists the OEM, Unicel and Pleatco numbers that the source documents treat as interchangeable, plus the cartridge size so you can confirm against your old filter.
The same numbers, on one page, are in the cross-reference lookup. A schedule for this part number, and the buy link, are on the replacement schedule and reorder page. Published intervals by brand are in the replace and clean calculator.
Master Spas 4CH-20 cartridge, 4-5/8" (117 mm) × 6-3/4" (171 mm), 20 sq ft. Unicel 4CH-20, Pleatco PHC25.
Unicel 4CH-20
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| OEM | |
|---|---|
| Unicel | 4CH-20 |
| Pleatco | PHC25 |
| Filbur | FC-0125 |
| Size | 4-5/8" (117 mm) × 6-3/4" (171 mm), 20 sq ft |
Sources
- Unicel 2026 Replacement Guide: OEM cross reference (Master Spas section), PDF p.45 (printed p.41); spec table PDF p.7 (printed p.3) (PDF)
- Filbur Catalog & Reference Guide: Product by Pool/Spa Manufacturer (OEM), Master Spas, printed p.43 (PDF p.22) (PDF)
Not in sources: no model/model-year fitment in sources; Unicel lists no OEM part number for this brand entry.
Full details → · All Master Spas spa filters · Which fitting you need · How to install it
Softub 4CH-20 cartridge, 4-5/8" (117 mm) × 6-3/4" (171 mm), 20 sq ft. Unicel 4CH-20, Pleatco not listed.
Unicel 4CH-20 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.
| OEM | |
|---|---|
| Unicel | 4CH-20 |
| Pleatco | not listed |
| Filbur | not listed |
| Size | 4-5/8" (117 mm) × 6-3/4" (171 mm), 20 sq ft |
Unverified. This row has not been fully confirmed against a second source. Gaps: single source (Unicel only); no OEM part number; no Pleatco equivalent; no Filbur equivalent; no model/model-year fitment in sources. Checked 2026-10-31: Softub's 2025 owner's manual and Softub dealers (SoftubDirect, SpaStore, Simply Spas, ezhottubparts) describe snap-on 5020/5015/5010 filters, and the threaded replacement SoftubDirect sells is 4CH-23DF; retailer tables that list 4CH-20 for Softub repeat the Unicel size with no OEM number. Checked 2026-11-03: Hot Tub Essentials (ProAqua 4CH-20) and Hot Tub Outpost (ProLine P4CH-20) list Softub among the brands for this size with no Softub OEM number, in wording that matches Unicel's own listing; not an independent source. Checked 2026-11-04: Filbur lists FC-0125 / 4CH-20 under Saratoga (that row prints 15 sq ft), Leisure Bay (20 sq ft), Softsider (20 sq ft) and Vita (25 sq ft, OEM PVT-25), not under Softub. Pleatco lists Unicel's Saratoga OEM 20241-238 as PSG25P4 at 25 sq ft, not as a Softub part. Still no second source for the Softub application. Checked 2026-11-06: a pass over the Filbur catalog PDF found no row that prints Softub next to FC-0125 / 4CH-20. The size table still prints that Filbur number at 20 sq ft (Pleatco cell PHC25), and one brand row still prints Vita OEM PVT-25 at 25 sq ft. Checked 2026-11-07: Filbur still does not print Softub on an FC-0125 / 4CH-20 row. A Filbur brand row still pairs 4CH-20 with Vita OEM PVT-25. Still unresolved. Checked 2026-11-08: Unicel's Softub section still lists only this 20 sq ft 4-5/8" x 6-3/4" 1-1/2" MPT cartridge, with no OEM. Pleatco's Softub spec line is PTL20W-SV-P4 for OEM 90-802, not 4CH-20. Filbur's text contains no Softub. Still unresolved.. Measure your old cartridge before ordering.
Sources
- Unicel 2026 Replacement Guide: OEM cross reference (Softub section), PDF p.55 (printed p.51); spec table PDF p.7 (printed p.3) (PDF)
Full details → · All Softub spa filters · Which fitting you need · How to install it
Saratoga Spas 4CH-20 cartridge (OEM 20241-238), 4-5/8" (117 mm) × 6-3/4" (171 mm), 20 sq ft. Unicel 4CH-20, Pleatco PSG25P4.
Unicel 4CH-20 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.
| OEM | 20241-238 |
|---|---|
| Unicel | 4CH-20 |
| Pleatco | PSG25P4 |
| Filbur | FC-0125 |
| Size | 4-5/8" (117 mm) × 6-3/4" (171 mm), 20 sq ft |
Sources
- Unicel 2026 Replacement Guide: Saratoga list PDF p.55: 20241-238 = 4CH-20, 4-5/8" x 6-3/4", 20 sq ft, 1-1/2" MPT. Spec table PDF p.7: 204 pleats, 20 sq ft. Price index PDF p.88: 20 sq ft. Vita list PDF p.63: PVT 25 = 4CH-20 at 25 sq ft. (PDF)
- Pleatco 2023 Catalog: Spec table PDF p.31: PSG25P4, OEM 20241-238, 4-3/4" x 6-1/2", 25 sq ft. Deactivated list: PHC25 replacement N/A. (PDF)
- Filbur Catalog & Reference Guide: Saratoga section PDF p.25: FC-0125 at 15 sq ft. Size table column 25. Vita section PDF p.28: 25 sq ft for PVT-25. (PDF)
Not in sources: Area 20 (Unicel spec, price index, Saratoga line) vs 25 (Unicel Vita line, Pleatco, Filbur Vita section, Filbur size-table column) vs 15 (Filbur Saratoga section). Length 6-3/4" vs Pleatco 6-1/2". Outside diameter 4-5/8" vs Pleatco 4-3/4"..
Full details → · All Saratoga Spas spa filters · Which fitting you need · How to install it