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.
Master Spas spa filter (6CH-940)
Master Spas swim spas
Replacement numbers
Unicel 6CH-940, Pleatco PWW50P3
Fits Master Spas swim spas.
Diameter 6" (152 mm)Length 8-1/4" (210 mm)45 sq ft1 model listedUnicel 6CH-940
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| Unicel | 6CH-940 |
|---|---|
| Pleatco | PWW50P3 |
| Filbur | FC-0359 |
| Top | semi-circular handle |
| Bottom | injection molded 1-1/2" SAE thread |
Bottom: injection molded 1-1/2" SAE thread
Drawn to scale from the listed diameter and length. Handles, threads and closed ends are drawn as symbols, not to scale. 45 sq ft media.
Master Spas files this cartridge as 6CH-940 cartridge, in the Master Spas swim spas group. Numbers on the row: Unicel 6CH-940; Pleatco PWW50P3; Filbur FC-0359. 6" across, 8-1/4" long, top semi-circular handle, bottom injection molded 1-1/2" SAE thread, 45 sq ft.
What the sources add about PWW50P3: Unicel: for use in Master Spas swim spas.
Master Spas applications recorded for this cartridge: Master Spas swim spas, no year range printed, listed by Unicel 2026 Replacement Guide.
Hold 6CH-940 next to 6CH-352 differs by Unicel 6CH-352, Pleatco PAS40-F2M, Filbur FC-0312, 8" long, bottom 2” male thread/MPT, 35 sq ft, OEM PMA-R1, note says Unicel: must remove black stand pipe. Filbur cross-references 6CH-352 to FC-0312 but lists FC-0312 at 6" x 7"; 6CH-402 differs by Unicel 6CH-402, Pleatco PMA40L-F2M, Filbur FC-0317, 9-1/2" long, bottom 2” male thread/MPT, 40 sq ft, OEM PMA40L-F2M, note says Unicel prints PMA40L-F2M (a Pleatco number) in its OEM column; Pleatco lists Master Spas Twilight OEM X268365 for PMA40L-F2M. Unicel: must remove black stand pipe.
Left blank on purpose: Unicel lists no OEM part number for this brand entry.
Source locations for this Master Spas row: Unicel 2026 Replacement Guide on 6CH-940 (OEM cross reference (Master Spas section), PDF p.45 (printed p.41); spec table PDF p.12 (printed p.8)). Pleatco 2023 Catalog on 6CH-940 (Unicel-to-Pleatco cross reference, PDF p.47). Filbur Catalog & Reference Guide on 6CH-940 (Unicel-to-Filbur reverse cross reference, printed p.66 (PDF p.34)).
Hot tubs listed for this cartridge
The rest of the Master Spas model list is the Master Spas filter by model and year lookup.
| Model / system | Years | Listed by |
|---|---|---|
| Master Spas swim spas | not given | Unicel 2026 Replacement 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. Brand notes: Master Spas Eco-Pur filters. Number formats: how Filbur, Unicel and Pleatco numbers compare.
The same 6CH-940 number is also on the Waterway Plastics page.
Other Master Spas cartridges
- 6CH-352 cartridge (OEM PMA-R1), 6" (152 mm) × 8" (203 mm)
- 6CH-402 cartridge (OEM PMA40L-F2M), 6" (152 mm) × 9-1/2" (241 mm)
- 7CH-322 cartridge, 7" (178 mm) × 8" (203 mm)
- C-7330 cartridge, 7" (178 mm) × 7-1/4" (184 mm)
- 4CH-252 cartridge (OEM X268521), 4-5/8" (117 mm) × 8" (203 mm)
- 4CH-949 cartridge, 4-15/16" (125 mm) × 13-1/2" (343 mm)
All 13 Master 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
-
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.
-
AquaChek SPA 6-in-1 Test Strips Listing title: reads total bromine, total chlorine, free chlorine, pH, total alkalinity and total hardness.
Unicel 6CH-940 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 (Master Spas section), PDF p.45 (printed p.41); spec table PDF p.12 (printed p.8) (PDF)
- Pleatco 2023 Catalog: Unicel-to-Pleatco cross reference, PDF p.47 (PDF)
- Filbur Catalog & Reference Guide: Unicel-to-Filbur reverse cross reference, printed p.66 (PDF p.34) (PDF)
Not in sources: Unicel lists no OEM part number for this brand entry.