PPM35TC / C-5423 / FC-3623
35 sq ft replacement filter cartridge • 5.1875″ OD × 11.3125″ long
Marquis built its Pacific-series tubs (the Euphoria, Reward, Retreat, Departure, and Voyager RS) between 1995 and 1999, and this is the cartridge they take. It's a 35-square-foot element with a closed top, no handle, and a single 1-5/8-inch hole in the bottom, so it seats one specific way. Marquis numbers it 370-215 and 20045, and the cross-references are Unicel C-5423 and Filbur FC-3623. If your Marquis is newer than 1999, it probably uses the handle-top PPM35SC instead. Same square footage, different fitting. Check whether your old cartridge has a closed cap or a bar handle before you order.
Compare on Amazon
PPM35TC 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 | PPM35TC | Primary |
| Unicel | C-5423 | Equivalent |
| Filbur | FC-3623 | Equivalent |
| OEM | Marquis 370-215 | Original Equipment |
| OEM | Marquis 20045 | Original Equipment |
Always verify dimensions and end-cap type before purchasing a replacement.
Compatible Hot Tubs & Spas
The PPM35TC (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 PPM35TC?
The PPM35TC is 5.1875 inches in outer diameter, 11.3125 inches long, with a closed top and an open bottom. Total filtration area is 35 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 PPM35TC?
PPM35TC is the same physical cartridge as C-5423, FC-3623, plus OEM versions like Marquis 370-215, Marquis 20045. Same dimensions (5.1875" × 11.3125"), 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 370-215 the same filter as the PPM35TC?
Yes. Marquis 370-215 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 370-215 (along with Marquis 20045) and PPM35TC, C-5423, FC-3623 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 PPM35TC?
Mid-size spa cartridges like the PPM35TC (35 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 PPM35TC?
The PPM35TC 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 PPM35TC?
The PPM35TC is compatible with: Marquis Reward, Marquis Euphoria. 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 | 11.3125″ |
| Top Type | Closed (solid end cap) |
| Bottom Type | Open (no end cap) |
| Filtration Area | 35 sq ft |
| Primary Brand | Pleatco |
| Part Number | PPM35TC |
Fitment notes
Closed top (no handle), 1-5/8 inch bottom hole. Marquis Pacific series 1995-1999: Euphoria, Reward, Retreat, Departure, Voyager RS.