Marquis Spas spa filter (C-5637)

Marquis Spas (listed as Pacific Marquis in the Filbur catalog)

Replacement numbers

Unicel C-5637, Pleatco PPM40-4

Fits Marquis Spas (listed as Pacific Marquis in the Filbur catalog).

Diameter 5-3/16" (132 mm)Length 19-5/8" (498 mm)40 sq ft

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UnicelC-5637
PleatcoPPM40-4 (as printed in the Filbur catalog Marquis Spas section (printed p.43); not found in the Pleatco 2023 Unicel cross reference)
FilburFC-3637
Top1-1/16" (27 mm) / open
Bottom1-5/8" (41 mm) / open
Ø 5-3/16" (132 mm)19-5/8" (498 mm)Side view · end views belowTopBottom
Top: 1-1/16" (27 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. 40 sq ft media.

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For Marquis Spas, C-5637 cartridge sits in Marquis Spas (listed as Pacific Marquis in the Filbur catalog). The cross-reference prints Unicel C-5637; Pleatco PPM40-4; Filbur FC-3637. 5-3/16" across, 19-5/8" long, top 1-1/16" / open, bottom 1-5/8" / open, 40 sq ft.

PPM40-4 carries this note from the catalogs: Old design (Unicel); Filbur lists it as Pacific Marquis 40. Neither source gives an OEM number.

PPM40-4 is the Pleatco string Filbur prints next to C-5637 (OEM C-5637 cartridge) on printed p.43. PPM40-4 itself is absent from Pleatco’s 2023 Unicel cross-reference.

Before ordering C-5637, compare it with C-5434 differs by Unicel C-5434, Pleatco PPM60TC, Filbur FC-3634, top closed, 60 sq ft, OEM 20043, note says Closed-top cartridge, listed by Unicel as Pacific Marquis (new). Unicel's spec table rates it 58 sq ft and notes the original was 40 sq ft (109 pleats), upgraded to 60 sq ft in the replacement. Unicel lists OEM 370-0216; Filbur prints 370-216.; and 5CH-512 differs by Unicel 5CH-512, no Pleatco number, no Filbur number, 16" long, top bar handle, bottom 2” male thread/MPT, 50 sq ft, OEM 20690, note says Marquis's own filter finder lists part 20690 as the threaded 50 sq ft filter for Crown Series spas from 2021, Elite models (Woodstock, Vegas, Hollywood, Broadway, Monaco Elite) from 2020, and the same Elite models in the 2018–2019 Celebrity Series. Two Marquis parts dealers describe 20690 as 5-3/16" x 16" with a handle top and 2" MPT thread, 50 sq ft, which matches Unicel's 5CH-512; they describe it as used on Celebrity Elite and V150 models rather than naming Crown. Marquis's 2026 Crown owner's manual describes a single 35 sq ft cartridge, which does not match the finder's 50 sq ft 20690 for Crown; see our Marquis model-year page..

Left blank on purpose: no OEM part number in sources; no model/model-year fitment in sources.

Source locations for this Marquis Spas row: Unicel 2026 Replacement Guide on C-5637 (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-5637 (Product by Pool/Spa Manufacturer (OEM), Marquis Spas, printed p.43 (PDF p.22)).

If you know the Marquis Spas model and not the part number, use the Marquis 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. Number formats: how Filbur, Unicel and Pleatco numbers compare.

Other Marquis Spas cartridges

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

Sources

Not in sources: no OEM part number in sources; no model/model-year fitment in sources.