PMA10 / C-3310 / FC-1001
9 sq ft replacement filter cartridge • 3.875″ OD × 7″ long
The PMA10 is a small inner filter, not a tub's main cartridge. It's just 9 square feet, under 4 inches across and 7 inches long. Master Spas uses it as the inner element on EcoPur filtration setups, as the plain circulation filter on non-EcoPur tubs built before 2004, and as the inner filter in the Clarity Elite. If your Master Spas takes two nested cartridges, this is the little one that sits inside the larger PMA45. Master Spas numbers it X268055 and X268057, and it crosses to Unicel C-3310 and Filbur FC-1001. Buy it together with the outer cartridge. Replacing only the inner element while the outer one is spent doesn't accomplish much.
Compare on Amazon
PMA10 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 | PMA10 | Primary |
| Unicel | C-3310 | Equivalent |
| Filbur | FC-1001 | Equivalent |
| OEM | Master Spas X268055 | Original Equipment |
| OEM | Master Spas X268057 | Original Equipment |
Always verify dimensions and end-cap type before purchasing a replacement.
Compatible Hot Tubs & Spas
The PMA10 (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.
| Brand | Model |
|---|---|
| Master Spas | Twilight Series |
| Master Spas | Legend |
| Master Spas | Clarity |
Frequently Asked Questions
What are the dimensions of the PMA10?
The PMA10 is 3.875 inches in outer diameter, 7 inches long, with an open top and an open bottom. Total filtration area is 9 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 PMA10?
PMA10 is the same physical cartridge as C-3310, FC-1001, plus OEM versions like Master Spas X268055, Master Spas X268057. Same dimensions (3.875" × 7"), 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.
Is the Master Spas X268055 the same filter as the PMA10?
Yes. Master Spas X268055 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 Master Spas X268055 (along with Master Spas X268057) and PMA10, C-3310, FC-1001 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 PMA10?
This is a small cartridge at 9 sq ft, often an inner or circulation filter rather than a tub's main element. It shows up most often in Master Spas tubs. There's so little media that it loads up fast, so plan on replacing it more often than a full-size spa filter, roughly once a year with regular use. Rinse it every few weeks, and swap it once the pleats stay grey after a soak or the material starts to soften and lose its shape.
How do I clean the PMA10?
The PMA10 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 PMA10?
The PMA10 is compatible with: Master Spas Twilight Series, Master Spas Legend, Master Spas Clarity. 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 | 3.875″ |
|---|---|
| Length | 7″ |
| Top Type | Open (no end cap) |
| Bottom Type | Open (no end cap) |
| Filtration Area | 9 sq ft |
| Primary Brand | Pleatco |
| Part Number | PMA10 |
Fitment notes
2-1/8 inch open top and bottom. Master Spas EcoPur inner/circulation filter (non-EcoPur pre-2004). Clarity Elite inner filter.