Hayward CX870-XRE Filter Cartridge
Hayward OEM number • 100 sq ft • 7″ OD × 25.5″ long
CX870-XRE is Hayward's number for this cartridge, not a part you have to buy from Hayward. The filter itself is a 100 square foot cartridge measuring 7 inches across and 25.5 inches long, and Pleatco, Unicel, and Filbur all build it. If you read CX870-XRE off an old cartridge or found it in your manual, any of the numbers below drops into the same housing.
Hayward also lists CX870RE against this cartridge. Different numbers on paper, same filter in the box.
Fitment notes
3-inch top and bottom openings. Hayward Super-Star-Clear C4000, C4000S, C4020. Also SwimClear C4020 (older).
What to buy instead
Replacements for the Hayward CX870-XRE
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 |
|---|---|---|
| Hayward | CX870-XRE | The number you searched |
| Pleatco | PA100N | Aftermarket equivalent |
| Unicel | C-7487 | Aftermarket equivalent |
| Filbur | FC-1270 | Aftermarket equivalent |
| Hayward | CX870RE | Other OEM number |
Full specs, the cartridge diagram, and the complete compatibility list live on the PA100N cartridge page. You can also see every 7″ × 25.5″ cartridge if you are checking a measurement rather than a part number.
Equipment that uses this cartridge
Looking for a different model? Browse every Hayward model we cover.
Frequently Asked Questions
What filter replaces the Hayward CX870-XRE?
The PA100N replaces it directly, and so does every cross-reference for it: C-7487, FC-1270. All of them are the same 100 sq ft cartridge at 7" outer diameter and 25.5" long. Buy whichever is cheapest at the time with solid recent reviews. The same cartridge also shows up as Hayward CX870RE, so those are not different filters either.
Is the Hayward CX870-XRE the same as the PA100N?
Yes, physically the same filter. Hayward CX870-XRE is an OEM number, meaning it is the code Hayward put on the cartridge that shipped with the equipment. Hayward 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 Hayward 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 Hayward CX870-XRE?
7 inches in outer diameter, 25.5 inches long, with 100 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.
Data updated July 2026