Master Spas spa filter (C-3310AM)

Master Spas Eco-Pur (inner)

Replacement numbers

Unicel C-3310AM, Pleatco PMA10

Fits Master Spas Eco-Pur (inner).

Diameter 3-7/8" (98 mm)Length 7" (178 mm)8 sq ft

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UnicelC-3310AM
PleatcoPMA10
Filburnot found in Filbur catalog
Top2-3/16" (56 mm) / open
Bottom2-3/16" (56 mm) / open
Ø 3-7/8" (98 mm)7" (178 mm)Side view · end views belowTopBottom
Top: 2-3/16" (56 mm) / open
Bottom: 2-3/16" (56 mm) / open
Drawn to scale from the listed diameter and length and open-end sizes. Handles, threads and closed ends are drawn as symbols, not to scale. 8 sq ft media.

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Master Spas files this cartridge as C-3310AM cartridge, in the Master Spas Eco-Pur (inner) group. Numbers on the row: Unicel C-3310AM; Pleatco PMA10. 3-7/8" across, 7" long, top 2-3/16" / open, bottom 2-3/16" / open, 8 sq ft.

What the sources add about PMA10: Unicel: antimicrobial media; used with a C-7330 or C-8341 outer cartridge in Eco-Pur systems.

Before ordering C-3310AM, compare it with 4CH-252 differs by Unicel 4CH-252, Pleatco PMA20-F2M, 4-5/8" diameter, 8" long, top molded cone handle, bottom 2” male thread/MPT, 25 sq ft, OEM X268521, note says Unicel: Master Spas original has 4-3/4" OD; and 6CH-352 differs by Unicel 6CH-352, Pleatco PAS40-F2M, Filbur FC-0312, 6" diameter, 8" long, top semi-circular handle, bottom 2” male thread/MPT, 35 sq ft, OEM PMA-R1, note says Unicel: must remove black stand pipe. Filbur cross-references 6CH-352 to FC-0312 but lists FC-0312 at 6" x 7".

Filbur does not have a number on this row. Search PMA10 or the Master Spas part you pulled out of the spa.

Left blank on purpose: no Filbur equivalent found in Filbur catalog; no model/model-year fitment in sources; Unicel lists no OEM part number for this brand entry.

Pages checked for PMA10: Unicel 2026 Replacement Guide on C-3310AM (OEM cross reference (Master Spas section), PDF p.45 (printed p.41); spec table PDF p.6 (printed p.2)). Pleatco 2023 Catalog on C-3310AM (Unicel-to-Pleatco cross reference, PDF p.47).

If you know the Master Spas model and not the part number, use the Master Spas filter by model and year lookup.

Check the cartridge you removed

Measure diameter, length, and both ends, then compare them with the figures above. The steps are in the measuring guide. Why the bottom decides whether it seals: open-end vs threaded filters. Power, the retainer, and not running the spa empty: how to install a cartridge. Brand notes: Master Spas Eco-Pur filters. Number formats: how Filbur, Unicel and Pleatco numbers compare.

Other Master Spas cartridges

All 13 Master Spas spa filters

Every number on this row, on one screen: cross-reference lookup. Published clean and replace intervals for this cartridge, and a buy link for the numbers above: replacement schedule and reorder. The interval comparison by brand: calculator.

Cleaner and test strips

Hose rinse and soak steps are in how to clean a cartridge. Named cleaners and strips are in filter cleaners and test strips.

Filter cleaner and test strips

Sources

Not in sources: no Filbur equivalent found in Filbur catalog; no model/model-year fitment in sources; Unicel lists no OEM part number for this brand entry.