PPM50TC / C-5346 / FC-3638
50 sq ft replacement filter cartridge • 5.1875″ OD × 14.125″ long
The PPM50TC is the 50-square-foot cartridge for Marquis Signature Series tubs from 1997 to 1999. Like the smaller Pacific-series filter it has a closed top and a 1-5/8-inch bottom hole, but it's noticeably longer at just over 14 inches. Marquis part numbers include 37-0217, 370-0236, and 20044, and it crosses to Unicel C-5346 and Filbur FC-3638. The closed-top design means there's only one way it goes in, and it's easy to tell apart from the newer handle-top Marquis cartridges. If you're not sure which Signature-era filter you have, go by length. This one's the tall one.
Compare on Amazon
PPM50TC 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 | PPM50TC | Primary |
| Unicel | C-5346 | Equivalent |
| Filbur | FC-3638 | Equivalent |
| OEM | Marquis 37-0217 | Original Equipment |
| OEM | Marquis 370-0236 | Original Equipment |
| OEM | Marquis 20044 | Original Equipment |
Always verify dimensions and end-cap type before purchasing a replacement.
Compatible Hot Tubs & Spas
The PPM50TC (or any of its cross-references) fits these spa models. Cartridge sizing occasionally shifted between model years, so it's worth confirming against your owner's manual or the cartridge label.
Frequently Asked Questions
What are the dimensions of the PPM50TC?
The PPM50TC is 5.1875 inches in outer diameter, 14.125 inches long, with a closed top and an open bottom. Total filtration area is 50 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 PPM50TC?
PPM50TC is the same physical cartridge as C-5346, FC-3638, plus OEM versions like Marquis 37-0217, Marquis 370-0236, Marquis 20044. Same dimensions (5.1875" × 14.125"), same closed 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.
Is the Marquis 37-0217 the same filter as the PPM50TC?
Yes. Marquis 37-0217 is an OEM number, the code the tub or pool builder stamps on the cartridge they ship. The filter itself is made by Pleatco, Unicel, or Filbur, so Marquis 37-0217 (along with Marquis 370-0236, Marquis 20044) and PPM50TC, C-5346, FC-3638 all point to one interchangeable cartridge. Buy whichever is cheapest with solid recent reviews, and just check that the dimensions match your old cartridge before you order.
How often should I replace the PPM50TC?
Mid-size spa cartridges like the PPM50TC (50 sq ft) usually last 12 to 24 months. It shows up most often in Marquis tubs. The real driver is use: a tub that gets daily soaks for a couple of people burns through cartridges about twice as fast as one used a few times a month. A good rhythm is a monthly hose rinse, a deep soak in cleaner at every water change (every three to four months), and replacement once the pleats tear, the seams stain brown, or a soak no longer brings post-clean pressure back to baseline.
How do I clean the PPM50TC?
The PPM50TC has a closed (solid) top cap, so water enters through the side and drains through the bottom only. 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 PPM50TC?
The PPM50TC is compatible with: Marquis Signature, Marquis Crown. Confirm against your owner's manual or the label inside the filter compartment, since some brands changed cartridge sizing between model years.
Dimensions
Specifications
| Outer Diameter | 5.1875″ |
|---|---|
| Length | 14.125″ |
| Top Type | Closed (solid end cap) |
| Bottom Type | Open (no end cap) |
| Filtration Area | 50 sq ft |
| Primary Brand | Pleatco |
| Part Number | PPM50TC |
Fitment notes
Closed top, 1-5/8 inch bottom hole. Marquis Signature Series 1997-1999 all models.