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.
PDC Spas OEM FLT-SWIM50-CART spa filter (4CH-949)
Synergy, Summit, Splash, Vitality, and dual-zone hot-tub side
Replacement numbers
Unicel 4CH-949, Pleatco PWW50L
Fits PDC Spas OEM FLT-SWIM50-CART.
Diameter 4-15/16" (125 mm)Length 13-1/2" (343 mm)50 sq ft1 model listedUnicel 4CH-949
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| Unicel | 4CH-949 |
|---|---|
| Pleatco | PWW50L (Cross-reference PDF p.47: 4CH-949 = PWW50L. Spec table PDF p.32: 5" × 13-3/16", handle, 1-1/2" female SAE, 3 oz, 50 sq ft, Waterway Teleweir 50, OEM 817-4050. Deactivated PDC570-AFS points at PWW50L; PDC’s 2025 guide does not print PDC570-AFS.) |
| Filbur | FC-0172 |
| Top | v-groove semi-circular handle |
| Bottom | 2" female SAE thread |
Bottom: 2" female SAE thread
Drawn to scale from the listed diameter and length. Handles, threads and closed ends are drawn as symbols, not to scale. 50 sq ft media.
For PDC Spas, 4CH-949 cartridge (OEM FLT-SWIM50-CART) sits in Synergy, Summit, Splash, Vitality, and dual-zone hot-tub side. The cross-reference prints OEM FLT-SWIM50-CART; Unicel 4CH-949; Pleatco PWW50L; Filbur FC-0172. 4-15/16" across, 13-1/2" long, top v-groove semi-circular handle, bottom 2" female SAE thread, 50 sq ft.
FLT-SWIM50-CART carries this note from the catalogs: Dimensions shown are Unicel’s: 4-15/16" × 13-1/2", v-groove handle, 210 pleats, 3 oz, 50 sq ft, 2" female SAE, note “For use on 1-1/2" male SAE stand pipe.” PDC’s 2025 guide rates FLT-SWIM50-CART at 50 sq ft, 5" × 13-1/16", 1-1/2" female SAE (38 mm), for Synergy, Summit, Splash, Vitality, and the hot-tub zone of dual-zone models, 2009 to present, and names Unicel 4CH-949. Pleatco prints PWW50L at 5" × 13-3/16", 1-1/2" female SAE, 50 sq ft, OEM 817-4050. Unicel’s Waterway line also prints 817-4050 as 4CH-949. PDC does not print 817-4050. Filbur’s size table prints FC-0172 at Unicel’s 13-1/2" and 2" female SAE.
4CH-949 (OEM FLT-SWIM50-CART), Pleatco side: Cross-reference PDF p.47: 4CH-949 = PWW50L. Spec table PDF p.32: 5" × 13-3/16", handle, 1-1/2" female SAE, 3 oz, 50 sq ft, Waterway Teleweir 50, OEM 817-4050. Deactivated PDC570-AFS points at PWW50L; PDC’s 2025 guide does not print PDC570-AFS..
FLT-SWIM50-CART, Filbur note: Dimensional listing PDF p.9 (printed p.17): FC-0172, 4-15/16" × 13-1/2", handle, 2" female SAE, 4CH-949, 50 sq ft. PDC Spas section does not list it..
Hot tubs named for FLT-SWIM50-CART: Synergy, Summit, Splash, Vitality, and the hot-tub zone of dual-zone models, years 2009 to present, listed by PDC Spas Common Replacement Filter Elements (2025) (FLT-SWIM50-CART, 50 sq ft top-mount. PDC names Unicel 4CH-949.).
4CH-949 is easy to confuse on the PDC Spas table. C-4326 differs by Unicel C-4326, Pleatco PRB25-IN, Filbur FC-2375, 13-5/16" long, top 2-1/8" / open, bottom 2-1/8" / open, 25 sq ft, OEM FLT-201TL, note says PDC’s 2025 guide: Luxury, Premium, SE and LX, 1990 to present, FLT-201TL, 25 sq ft, 5" × 13-5/16", 2-1/8" holes, named as Unicel C-4326. Unicel’s spec table prints C-4326 at 4-15/16" × 13-5/16", 106 pleats, 3 oz, 25 sq ft. Pleatco prints PRB25-IN at 5" × 13-5/16". Filbur’s size table crosses FC-2375 to C-4326. Filbur’s PDC section prints FC-2370 as C-4325, which is a different, 11-7/8" cartridge.. C-4975 differs by Unicel C-4975, Pleatco PRB75, Filbur FC-2395, 20-1/8" long, top 2-1/8" / open, bottom 2-1/8" / open, 75 sq ft, OEM FLT-SWIM75-CART, note says PDC’s 2025 guide: TruSwim, 2016 to present, FLT-SWIM75-CART, 75 sq ft, 5" × 20-1/8", 2" center hole, named as Unicel C-4975. Unicel’s spec table prints C-4975 at 4-15/16" × 20-1/8", 2-1/8" open both ends, 210 pleats, 3 oz, 75 sq ft. Pleatco prints PRB75 at 5" × 20-1/8", 2-1/8" both ends, 3 oz, 75 sq ft. Filbur prints FC-2395 at 4-15/16" × 20-1/8", 2-1/8" open, 75 sq ft. The opening PDC prints (2") is not the 2-1/8" the three catalogs print. Dimensions on this row are Unicel’s..
Left blank on purpose: Length 13-1/16" (PDC) vs 13-3/16" (Pleatco) vs 13-1/2" (Unicel, Filbur). Thread wording: PDC and Pleatco 1-1/2" female SAE; Unicel and Filbur 2" female SAE, with Unicel’s note that it fits a 1-1/2" male SAE standpipe. Diameter 5" (PDC, Pleatco) vs 4-15/16" (Unicel, Filbur). Not in Filbur’s PDC section..
Source locations for this PDC Spas row: PDC Spas (manufacturer filter guide, 2025) on 4CH-949 (Synergy, Summit, Splash, Vitality, and the hot-tub zone of dual-zone models, 2009–present: FLT-SWIM50-CART, 50 sq ft, 5" × 13-1/16", 1-1/2" female SAE (38 mm), Unicel 4CH-949). Unicel 2026 Replacement Guide on 4CH-949 (Spec table PDF p.9 (printed p.5): 4CH-949, 4-15/16" × 13-1/2", 210 pleats, 3 oz, 50 sq ft, 2" female SAE, note for a 1-1/2" male SAE standpipe. Waterway line: 817-4050 = 4CH-949.). Pleatco 2023 Catalog on 4CH-949 (PDF p.32: PWW50L, 5" × 13-3/16", 1-1/2" female SAE, 50 sq ft. PDF p.47: 4CH-949 = PWW50L.). Filbur Catalog & Reference Guide on 4CH-949 (PDF p.9 (printed p.17): FC-0172 = 4CH-949, 13-1/2", 2" female SAE, 50 sq ft).
Hot tubs listed for this cartridge
The rest of the PDC Spas model list is the PDC Spas filter by model and year lookup.
| Model / system | Years | Listed by |
|---|---|---|
| Synergy, Summit, Splash, Vitality, and the hot-tub zone of dual-zone models (FLT-SWIM50-CART, 50 sq ft top-mount. PDC names Unicel 4CH-949.) | 2009 to present | PDC Spas Common Replacement Filter Elements (2025) |
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-949 number is also on the Master Spas, Waterway Plastics pages.
Other PDC Spas cartridges
- C-4326 cartridge (OEM FLT-201TL), 4-15/16" (125 mm) × 13-5/16" (338 mm)
- C-4975 cartridge (OEM FLT-SWIM75-CART), 4-15/16" (125 mm) × 20-1/8" (511 mm)
- C-4405 cartridge (OEM FLT-171-CART), 4-15/16" (125 mm) × 6-5/8" (168 mm)
- PRB7B cartridge (OEM FLT-118), 5" (127 mm) × 4-5/8" (117 mm)
- 4CH-15 cartridge (OEM FLT-1000-CART), 4-5/8" (117 mm) × 5-3/16" (132 mm)
- C-4310 cartridge (OEM FLT-101SK), 4-1/4" (108 mm) × 4" (102 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.
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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 4CH-949 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
- PDC Spas (manufacturer filter guide, 2025): Synergy, Summit, Splash, Vitality, and the hot-tub zone of dual-zone models, 2009–present: FLT-SWIM50-CART, 50 sq ft, 5" × 13-1/16", 1-1/2" female SAE (38 mm), Unicel 4CH-949 (PDF)
- Unicel 2026 Replacement Guide: Spec table PDF p.9 (printed p.5): 4CH-949, 4-15/16" × 13-1/2", 210 pleats, 3 oz, 50 sq ft, 2" female SAE, note for a 1-1/2" male SAE standpipe. Waterway line: 817-4050 = 4CH-949. (PDF)
- Pleatco 2023 Catalog: PDF p.32: PWW50L, 5" × 13-3/16", 1-1/2" female SAE, 50 sq ft. PDF p.47: 4CH-949 = PWW50L. (PDF)
- Filbur Catalog & Reference Guide: PDF p.9 (printed p.17): FC-0172 = 4CH-949, 13-1/2", 2" female SAE, 50 sq ft (PDF)
Not in sources: Length 13-1/16" (PDC) vs 13-3/16" (Pleatco) vs 13-1/2" (Unicel, Filbur). Thread wording: PDC and Pleatco 1-1/2" female SAE; Unicel and Filbur 2" female SAE, with Unicel’s note that it fits a 1-1/2" male SAE standpipe. Diameter 5" (PDC, Pleatco) vs 4-15/16" (Unicel, Filbur). Not in Filbur’s PDC section..