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-45)
Master Spas
Replacement numbers
Unicel 6CH-45, Pleatco PTL45W-P-4
Fits Master Spas.
Diameter 6" (152 mm)Length 12-3/8" (314 mm)45 sq ftUnicel 6CH-45
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| Unicel | 6CH-45 |
|---|---|
| Pleatco | PTL45W-P-4 (as printed in the Filbur catalog Master Spas section (printed p.43); not found in the Pleatco 2023 Unicel cross reference) |
| Filbur | FC-0330 |
| Top | semi-circular handle |
| Bottom | 1-1/2” male thread/MPT |
Bottom: 1-1/2” male thread/MPT
Drawn to scale from the listed diameter and length. Handles, threads and closed ends are drawn as symbols, not to scale. 45 sq ft media.
Master Spas is the group name on the Master Spas row 6CH-45 cartridge. Match these numbers: Unicel 6CH-45; Pleatco PTL45W-P-4; Filbur FC-0330. 6" across, 12-3/8" long, top semi-circular handle, bottom 1-1/2” male thread/MPT, 45 sq ft.
PTL45W-P-4 is the Pleatco string Filbur prints next to 6CH-45 (OEM 6CH-45 cartridge) on printed p.43. PTL45W-P-4 itself is absent from Pleatco’s 2023 Unicel cross-reference.
6CH-45 is easy to confuse on the Master Spas table. 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. 6CH-940 differs by Unicel 6CH-940, Pleatco PWW50P3, Filbur FC-0359, 8-1/4" long, bottom injection molded 1-1/2" SAE thread, note says Unicel: for use in Master Spas swim spas.
Left blank on purpose: no model/model-year fitment in sources; Unicel lists no OEM part number for this brand entry. Checked 2026-11-06: Filbur's size table and Freedom Spas section print FC-0330 / 6CH-45 at 6 x 12-1/4 in, against Unicel's 12-3/8 in kept on this row. Freedom model names are on the Freedom Spas fitment page..
Pages checked for PTL45W-P-4: Unicel 2026 Replacement Guide on 6CH-45 (OEM cross reference (Master Spas section), PDF p.45 (printed p.41); spec table PDF p.12 (printed p.8)). Filbur Catalog & Reference Guide on 6CH-45 (Product by Pool/Spa Manufacturer (OEM), Master Spas, printed p.43 (PDF p.22)).
If you know the Master Spas model and not the part number, use the Master Spas filter by model and year lookup.
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-45 number is also on the Freedom Spas page.
Other Master Spas cartridges
- 6CH-402 cartridge (OEM PMA40L-F2M), 6" (152 mm) × 9-1/2" (241 mm)
- 6CH-940 cartridge, 6" (152 mm) × 8-1/4" (210 mm)
- 6CH-352 cartridge (OEM PMA-R1), 6" (152 mm) × 8" (203 mm)
- 4CH-949 cartridge, 4-15/16" (125 mm) × 13-1/2" (343 mm)
- 7CH-322 cartridge, 7" (178 mm) × 8" (203 mm)
- C-7330 cartridge, 7" (178 mm) × 7-1/4" (184 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
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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.
Unicel 6CH-45 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)
- 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. Checked 2026-11-06: Filbur's size table and Freedom Spas section print FC-0330 / 6CH-45 at 6 x 12-1/4 in, against Unicel's 12-3/8 in kept on this row. Freedom model names are on the Freedom Spas fitment page..