Marquis 20091 Filter Cartridge
Marquis OEM number • 50 sq ft • 5.25″ OD × 12.1875″ long
20091 is Marquis's number for this cartridge, not a part you have to buy from Marquis. The filter itself is a 50 square foot cartridge measuring 5.25 inches across and 12.1875 inches long, and Pleatco, Unicel, and Filbur all build it. If you read 20091 off an old cartridge or found it in your manual, any of the numbers below drops into the same housing.
Marquis also lists 20041 and 370-0237 against this cartridge. Different numbers on paper, same filter in the box.
Fitment notes
Bar handle top with a 2 inch male threaded bottom fitting (Pleatco's F2M adapter). The 50 sq ft member of the new-design Marquis pair: the PPM35SC-F2M is the same 12-1/2 inch body at 35 sq ft. Marquis's own filter chart puts the 2000-2021 Signature Series on part 20091, which Unicel resolves to this cartridge, and lists the 35 as the alternative for the same tubs, so read the rating off your old cartridge. Unicel notes its 5CH-502 was formerly numbered C-5303, and that the same cartridge fits some Cal Spas models. Replaces Marquis OEM 20041, 20091 and 370-0237.
What to buy instead
Replacements for the Marquis 20091
Each button searches Amazon for one of the numbers this cartridge is sold under. The OEM version is usually the most expensive of the set and the aftermarket versions are the same physical filter, so it is worth checking all of them before you order.
Every number for this filter
| Brand | Part Number | Type |
|---|---|---|
| Marquis | 20091 | The number you searched |
| Pleatco | PPM50SC-F2M | Aftermarket equivalent |
| Unicel | 5CH-502 | Aftermarket equivalent |
| Filbur | FC-0195 | Aftermarket equivalent |
| Marquis | 20041 | Other OEM number |
| Marquis | 370-0237 | Other OEM number |
Full specs, the cartridge diagram, and the complete compatibility list live on the PPM50SC-F2M cartridge page. You can also see every 5.25″ × 12.1875″ cartridge if you are checking a measurement rather than a part number.
Equipment that uses this cartridge
Looking for a different model? Browse every Marquis model we cover.
Frequently Asked Questions
What filter replaces the Marquis 20091?
The PPM50SC-F2M replaces it directly, and so does every cross-reference for it: 5CH-502, FC-0195. All of them are the same 50 sq ft cartridge at 5.25" outer diameter and 12.1875" long. Buy whichever is cheapest at the time with solid recent reviews. The same cartridge also shows up as Marquis 20041, Marquis 370-0237, so those are not different filters either.
Is the Marquis 20091 the same as the PPM50SC-F2M?
Yes, physically the same filter. Marquis 20091 is an OEM number, meaning it is the code Marquis put on the cartridge that shipped with the equipment. Marquis does not manufacture cartridges. Pleatco, Unicel, and Filbur do, and they sell the identical part under their own numbers at a lower price. Match the dimensions against your old cartridge before ordering and you are covered.
Do I have to buy the Marquis version?
No. Nothing about the housing requires an OEM-branded cartridge, and the warranty on your equipment is not voided by using an aftermarket filter that meets the same spec. The reason to buy OEM is convenience, not performance. The reason not to is price, which is often a meaningful gap for an identical part. What matters is that outer diameter, length, and end-cap style all match.
What size is the Marquis 20091?
5.25 inches in outer diameter, 12.1875 inches long, with 50 square feet of filter media. Both measurements need to land within about an eighth of an inch, and the end caps have to match so the cartridge seats correctly when you close the lid. Measure your old one rather than trusting a number that has worn off the label.
Last verified August 2026