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.
Marquis Spas OEM 20045 spa filter (C-5423)
Marquis Spas (listed as Pacific Marquis in the Filbur catalog)
Replacement numbers
Unicel C-5423, Pleatco PPM35TC
Fits Marquis Spas OEM 20045, 370-0215.
Diameter 5-3/16" (132 mm)Length 11-15/16" (303 mm)35 sq ft1 model listedUnicel C-5423
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| Unicel | C-5423 |
|---|---|
| Pleatco | PPM35TC (as printed in the Filbur catalog Marquis Spas section (printed p.42); not found in the Pleatco 2023 Unicel cross reference) |
| Filbur | FC-3623 |
| Top | closed |
| Bottom | 1-5/8" (41 mm) / open |
Bottom: 1-5/8" (41 mm) / open
Drawn to scale from the listed diameter and length and open-end sizes. Handles, threads and closed ends are drawn as symbols, not to scale. 35 sq ft media.
For Marquis Spas, C-5423 cartridge (OEM 20045) sits in Marquis Spas (listed as Pacific Marquis in the Filbur catalog). The cross-reference prints OEM 20045, 370-0215; Unicel C-5423; Pleatco PPM35TC; Filbur FC-3623. 5-3/16" across, 11-15/16" long, top closed, bottom 1-5/8" / open, 35 sq ft.
Catalog note for 20045: Closed-top cartridge. Unicel's spec table rates it 34 sq ft and notes the original was 25 sq ft (115 pleats), upgraded to 35 sq ft in the replacement. Unicel lists OEM 370-0215; Filbur prints 370-215.
PPM35TC is the Pleatco string Filbur prints next to C-5423 (OEM 20045) on printed p.42. PPM35TC itself is absent from Pleatco’s 2023 Unicel cross-reference.
Model list attached to C-5423 cartridge (OEM 20045): Marquis Signature Series, years Pre-1997, listed by Marquis Spas filter finder (slip-on 35 sq ft, part 20045).
C-5423 is easy to confuse on the Marquis Spas table. 5CH-352 differs by Unicel 5CH-352, Pleatco PPM35SC-F2M, Filbur FC-0196, 12-1/2" long, top bar handle, bottom 2” male thread/MPT, OEM 20042, note says Pleatco 2023 lists OEM 20042, 370-0242 and 370-0243 for PPM35SC-F2M; Filbur lists OEM 370-0242 for FC-0196 and prints N/A in its Pleatco column.. 5CH-502 differs by Unicel 5CH-502, Pleatco PPM50SC-F2M, Filbur FC-0195, 12-1/2" long, top bar handle, bottom 2” male thread/MPT, 50 sq ft, OEM 20041, note says Unicel notes this part number was formerly C-5303, and also lists the cartridge under Cal Spas. Filbur prints the Pleatco number as PPM350SC-F2M; Pleatco's own catalog and its Filbur-to-Pleatco table give PPM50SC-F2M, which is what is shown here..
Left blank on purpose: Unicel notes the original 20045 was a 25 sq ft cartridge, while Marquis's finder calls it 35 sq ft.
Source locations for this Marquis Spas row: Unicel 2026 Replacement Guide on C-5423 (OEM cross reference (Marquis Spas section), PDF p.44 (printed p.40); spec table PDF p.10 (printed p.6)). Filbur Catalog & Reference Guide on C-5423 (Product by Pool/Spa Manufacturer (OEM), Marquis Spas, printed p.42 (PDF p.22)). Marquis Spas (manufacturer filter finder) on C-5423 (Filter Finder (series, model years, slip-on/threaded, sq ft, part number): Signature Series pre-1997, slip-on 35, 20045).
Hot tubs listed for this cartridge
The rest of the Marquis Spas model list is the Marquis Spas filter by model and year lookup.
| Model / system | Years | Listed by |
|---|---|---|
| Marquis Signature Series (slip-on 35 sq ft, part 20045) | Pre-1997 | Marquis Spas filter finder |
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.
Other Marquis Spas cartridges
- 5CH-352 cartridge (OEM 20042), 5-3/16" (132 mm) × 12-1/2" (318 mm)
- 5CH-502 cartridge (OEM 20041), 5-3/16" (132 mm) × 12-1/2" (318 mm)
- C-5346 cartridge (OEM 20044), 5-3/16" (132 mm) × 14-1/8" (359 mm)
- 5CH-512 cartridge (OEM 20690), 5-3/16" (132 mm) × 16" (406 mm)
- C-5434 cartridge (OEM 20043), 5-3/16" (132 mm) × 19-5/8" (498 mm)
All 9 Marquis 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 C-5423 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 (Marquis Spas section), PDF p.44 (printed p.40); spec table PDF p.10 (printed p.6) (PDF)
- Filbur Catalog & Reference Guide: Product by Pool/Spa Manufacturer (OEM), Marquis Spas, printed p.42 (PDF p.22) (PDF)
- Marquis Spas (manufacturer filter finder): Filter Finder (series, model years, slip-on/threaded, sq ft, part number): Signature Series pre-1997, slip-on 35, 20045 (web page)
Not in sources: Unicel notes the original 20045 was a 25 sq ft cartridge, while Marquis's finder calls it 35 sq ft.