Marquis Spas OEM 20499 spa filter (5CH-902AM)

Marquis Spas (listed as Pacific Marquis in the Filbur catalog) Unverified: no Pleatco equivalent; no Filbur equivalent; no Marquis document found. Checked 2026-11-01: two spa dealers confirm OEM 20499 as a 90 sq ft, ~30" threaded swim-spa cartridge with a handle (one also gives 20496 as the earlier number), but give the outside diameter as about 5-1/4" to 5-1/2" against Unicel's 5-3/16", and one describes a fine ~1.85" thread rather than 2" MPT Checked 2026-11-04: Filbur's Marquis section does not list 20499 or 5CH-902AM. OGS Pool and Spa's listing prints 5-3/16" x 30", handle, a 2" bottom and 90 sq ft, matching Unicel's diameter and length, but it does not say whether that 2" bottom is MPT or the fine thread Mastercraft describes. Checked 2026-11-06: Parts4tubs lists 5CH-902AM as a Unicel cartridge for Marquis Spas and reprints the catalog line "Cartridge, 90sqft, Bar ht, 2"mpt b, 5-3/16", 30", 4oz" (UPC 678285250115). That matches Unicel's diameter, length and 2" MPT wording. It is not a separate measurement of the fine thread. Checked 2026-11-07: no new measurement of the thread. A listing that reprints Unicel’s 2" MPT line does not settle the fine-thread description from 2026-11-01. Still unresolved. Checked 2026-11-08: Unicel PDF p.10 (spec) and PDF p.44 (Marquis OEM) still print 5CH-902AM at 5-3/16" x 30", 2" MPT, 90 sq ft, OEM 20499 and 370-0694. Pleatco 2023 and Filbur have no 5CH-902 and no 20499. No new measurement of the fine thread. Still unresolved.

Replacement numbers

Unicel 5CH-902AM

Fits Marquis Spas OEM 20499, 370-0694.

Diameter 5-3/16" (132 mm)Length 30" (762 mm)90 sq ft2 models listed

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Unicel5CH-902AM
Pleatconot found in source
Filburnot found in Filbur catalog
Topbar handle
Bottom2” male thread/MPT
Ø 5-3/16" (132 mm)30" (762 mm)Side view · end views belowTopBottom
Top: bar handle
Bottom: 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. 90 sq ft media.

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Marquis Spas files this cartridge as 5CH-902AM cartridge (OEM 20499), in the Marquis Spas (listed as Pacific Marquis in the Filbur catalog) group. Numbers on the row: OEM 20499, 370-0694; Unicel 5CH-902AM. 5-3/16" across, 30" long, top bar handle, bottom 2” male thread/MPT, 90 sq ft.

20499 carries this note from the catalogs: Made with antimicrobial filter media (Unicel spec note). Only the Unicel 2026 guide lists it among the catalogs. Two spa dealers sell OEM 20499 for Marquis ATV swim spas with matching area, length and handle, but a slightly larger diameter.

Marquis Spas applications recorded for this cartridge: Marquis ATV 14 and ATV 17 swim spas (ATV 14 Sport, ATV 14 Slash, ATV 17 Sport, ATV 17 Kona), no year range printed, listed by Marquis spa dealer listings (some use two filters); Marquis V174S and V174K swim spas, years 2023 and newer (select), listed by Marquis spa dealer listings (two 90 sq ft filters).

Before ordering 5CH-902AM, compare it with C-5434 differs by Unicel C-5434, Pleatco PPM60TC, Filbur FC-3634, 19-5/8" long, top closed, bottom 1-5/8" / open, 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, 16" long, 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..

Pleatco and Filbur do not have a number on this row. Search 20499 or the Marquis Spas part you pulled out of the spa.

Left blank on purpose: no Pleatco equivalent; no Filbur equivalent; no Marquis document found. Checked 2026-11-01: two spa dealers confirm OEM 20499 as a 90 sq ft, ~30" threaded swim-spa cartridge with a handle (one also gives 20496 as the earlier number), but give the outside diameter as about 5-1/4" to 5-1/2" against Unicel's 5-3/16", and one describes a fine ~1.85" thread rather than 2" MPT Checked 2026-11-04: Filbur's Marquis section does not list 20499 or 5CH-902AM. OGS Pool and Spa's listing prints 5-3/16" x 30", handle, a 2" bottom and 90 sq ft, matching Unicel's diameter and length, but it does not say whether that 2" bottom is MPT or the fine thread Mastercraft describes. Checked 2026-11-06: Parts4tubs lists 5CH-902AM as a Unicel cartridge for Marquis Spas and reprints the catalog line "Cartridge, 90sqft, Bar ht, 2"mpt b, 5-3/16", 30", 4oz" (UPC 678285250115). That matches Unicel's diameter, length and 2" MPT wording. It is not a separate measurement of the fine thread. Checked 2026-11-07: no new measurement of the thread. A listing that reprints Unicel’s 2" MPT line does not settle the fine-thread description from 2026-11-01. Still unresolved. Checked 2026-11-08: Unicel PDF p.10 (spec) and PDF p.44 (Marquis OEM) still print 5CH-902AM at 5-3/16" x 30", 2" MPT, 90 sq ft, OEM 20499 and 370-0694. Pleatco 2023 and Filbur have no 5CH-902 and no 20499. No new measurement of the fine thread. Still unresolved..

Pages checked for 20499: Unicel 2026 Replacement Guide on 5CH-902AM (OEM cross reference (Marquis Spas section), PDF p.44 (printed p.40); spec table PDF p.10 (printed p.6)). Southern Leisure Spas (spa dealer listing) on 5CH-902AM (replaces Marquis 20499 and 20496; ~90 sq ft, ~30" body, closed top with handle, ~2" male thread, OD ~5-1/4" to 5-1/2"; Marquis ATV 14/17 and select 2023+ V174S/V174K). Mastercraft Pool and Spa (spa dealer listing) on 5CH-902AM (Marquis P/N 20499, 90 sq ft, 31.5" long, 5.5" OD, bar handle, threaded bottom; Marquis ATV 14 and ATV 17 swim spas). OGS Pool and Spa (spa dealer listing) on 5CH-902AM (Product description fetched 2026-11-04: Marquis ATV Models, diameter 5 3/16", length 30", top handle, bottom 2", 90 sq ft, Microban. Does not say MPT or fine thread.). Parts4tubs (Unicel cartridge listing) on 5CH-902AM (Fetched 2026-11-06: Unicel 5CH-902AM for Marquis Spas. Catalog description repeats "90sqft, Bar ht, 2"mpt b, 5-3/16", 30", 4oz". UPC 678285250115. Not an independent thread measurement.).

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 / systemYearsListed by
Marquis ATV 14 and ATV 17 swim spas (ATV 14 Sport, ATV 14 Slash, ATV 17 Sport, ATV 17 Kona) (some use two filters)not givenMarquis spa dealer listings
Marquis V174S and V174K swim spas (two 90 sq ft filters)2023 and newer (select)Marquis spa dealer listings

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

Unverified. This row has not been fully confirmed against a second source. Gaps: no Pleatco equivalent; no Filbur equivalent; no Marquis document found. Checked 2026-11-01: two spa dealers confirm OEM 20499 as a 90 sq ft, ~30" threaded swim-spa cartridge with a handle (one also gives 20496 as the earlier number), but give the outside diameter as about 5-1/4" to 5-1/2" against Unicel's 5-3/16", and one describes a fine ~1.85" thread rather than 2" MPT Checked 2026-11-04: Filbur's Marquis section does not list 20499 or 5CH-902AM. OGS Pool and Spa's listing prints 5-3/16" x 30", handle, a 2" bottom and 90 sq ft, matching Unicel's diameter and length, but it does not say whether that 2" bottom is MPT or the fine thread Mastercraft describes. Checked 2026-11-06: Parts4tubs lists 5CH-902AM as a Unicel cartridge for Marquis Spas and reprints the catalog line "Cartridge, 90sqft, Bar ht, 2"mpt b, 5-3/16", 30", 4oz" (UPC 678285250115). That matches Unicel's diameter, length and 2" MPT wording. It is not a separate measurement of the fine thread. Checked 2026-11-07: no new measurement of the thread. A listing that reprints Unicel’s 2" MPT line does not settle the fine-thread description from 2026-11-01. Still unresolved. Checked 2026-11-08: Unicel PDF p.10 (spec) and PDF p.44 (Marquis OEM) still print 5CH-902AM at 5-3/16" x 30", 2" MPT, 90 sq ft, OEM 20499 and 370-0694. Pleatco 2023 and Filbur have no 5CH-902 and no 20499. No new measurement of the fine thread. Still unresolved.. Measure your old cartridge before ordering.

Sources