PPM40 / C-5637 / FC-3637
40 sq ft replacement filter cartridge • 5.1875″ OD × 19.625″ long
Compare on Amazon
PPM40 replacements on Amazon
The buttons below pull up Amazon results for each cross-reference part number. Same physical cartridge, different stickers, often different prices. Cross-shop and pick the cheapest option that has solid recent reviews.
Cross-Reference & Interchangeable Part Numbers
| Brand | Part Number | Type |
|---|---|---|
| Pleatco | PPM40 | Primary |
| Unicel | C-5637 | Equivalent |
| Filbur | FC-3637 | Equivalent |
Always verify dimensions and end-cap type before purchasing a replacement.
Frequently Asked Questions
What are the dimensions of the PPM40?
The PPM40 is 5.1875 inches in outer diameter, 19.625 inches long, with an open top and an open bottom. Total filtration area is 40 square feet. Before ordering, pull your existing cartridge and measure it yourself, or check the label inside the housing. OD and length both have to match within about an eighth of an inch, and the end-cap style needs to match exactly so the cartridge seats properly when the lid closes.
What other part numbers are interchangeable with the PPM40?
PPM40 is the same physical cartridge as C-5637, FC-3637. Same dimensions (5.1875" × 19.625"), same open top, same open bottom. The Pleatco, Unicel, and Filbur boxes ship the same media inside, just with different stickers. The only thing to watch is the end-cap style: if a cross-reference has a slightly different cap design, it may not seat right in your housing.
How often should I replace the PPM40?
Most filter cartridges last between 12 and 24 months. Pull the PPM40 every few months for a hose rinse, soak it in cleaner quarterly, and replace it when the pleats are torn, channeling, or won't come clean. Bather load, water chemistry, and how often you actually clean it all matter more than the calendar.
How do I clean the PPM40?
The PPM40 has open ends on both top and bottom, so water flows straight through. Pull the cartridge from the housing and hose it down. Hit the pleats from above at about a 45-degree angle so water rinses debris out instead of packing it deeper, and work top to bottom while rotating the cartridge. Skip the pressure washer. The high pressure tears or collapses pleats, and once that happens you've lost media that doesn't come back. Every few months (or at every water change, whichever comes first), do a deep clean: overnight soak in a hot tub filter cleaner, then a thorough rinse. If your cartridge has a closed end cap, let it dry before reinstalling so you don't trap moisture inside the cartridge core.
Which hot tubs and spas use the PPM40?
Pull your existing cartridge and read the part number off the end cap, or check the label inside the filter compartment. That's the most reliable way to confirm compatibility.
Dimensions
Specifications
| Outer Diameter | 5.1875″ |
|---|---|
| Length | 19.625″ |
| Top Type | Open (no end cap) |
| Bottom Type | Open (no end cap) |
| Filtration Area | 40 sq ft |
| Primary Brand | Pleatco |
| Part Number | PPM40 |
Fitment notes
Open at both ends, 1-1/16 and 1-5/8 inch openings. The old-design Pacific Marquis 40. Same 19-5/8 inch length as the PPM60, but that one has a closed top and holds 60 sq ft, so match the top end cap as well as the length. Neither sheet publishes a Marquis OEM number for this cartridge.