Pleatco PRB25-IN = Unicel C-4326 = Filbur FC-2375
25 sq ft hot tub filter, 5" diameter × 13-5/16" long. Top: 2-1/8" open · Bottom: 2-1/8" open. Pleatco application: Dynamic Series I RDC-25, I RDC-25S, Dynamic Series II & II RTL/RCF-25, Dynamic Series IV- DFM, DFML, Waterway 25 In-Line, Custom Molded Products.
Interchangeable cartridges
- Unicel C-4326 confirmed by: Pleatco p.47 (Unicel to Pleatco cross reference) Unicel p.9 (Cartridges by series (dimensional listing))
- Filbur FC-2375 confirmed by: Pleatco p.48 (Filbur to Pleatco cross reference) Filbur p.33 (Reverse cross reference (Unicel to Filbur))
Published dimensions, side by side
Each manufacturer measures a little differently. Compare these with your old cartridge.
Where to buy
Search any retailer for C-4326 or PRB25-IN or FC-2375. These are the same cartridge under different brand names.
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OEM part numbers this cartridge replaces
As printed in the cited aftermarket catalogs. Match the number on your old cartridge or in your spa manual exactly.
Hot tub brands that use it
From the spa-manufacturer cross reference in the Unicel 2026 Replacement Guide. A brand may use several sizes, so check your measurements.
- Accent Spas Unicel p.26
- Acryx-Maax Spas (Canada) Unicel p.26
- Apollo Spas Unicel p.27
- Aqua Mystic Unicel p.27
- Beachcomber (OEM 3005845) Unicel p.29
- Blue Falls Mfg. Ltd. (Canada) Unicel p.29
- Coast Mountain Spas (Canada) Unicel p.31
- Coleman Spas (OEM 100586, 3301-2242) Unicel p.32
- Custom Molded Products (models: Top Mount Skim, EZ Twist Top Mount Skim, Top Load Pressure; OEM 25392) Unicel p.33
- Dakota Spas Unicel p.33
- Emerald Spas Unicel p.35
- Great Lakes Home & Resort Unicel p.36
- Honey Tubs Unicel p.39
- Hot Spot (OEM 33521) Unicel p.39
- Hot Springs Spas (OEM 33521) Unicel p.39
- Islander Spas Unicel p.41
- Jacuzzi Premium (models: J200 Series; OEM 373045) Unicel p.42
- Moonwater Spas Unicel p.45
- Nordic Hot Tubs Unicel p.46
- Orca Bay Spas (OEM 2501) Unicel p.46
- PDC Spas Unicel p.47
- Pentair Pool Prod (models: Dynamic Series I RDC-25, Dynamic Series I RDC-25S, Dynamic Series II & III RTL/RCF-25, Dynamic Series IV - DFM,DFML; OEM R173429) Unicel p.47
- Pentair Pool Prod - Rainbow Plastics (models: Dynamic Series IV - DFM,DFML, Dynamic Series I - Model RDC, Dynamic Series II & III - RTL/RCF; OEM 17-2327) Unicel p.52
- QCA Unicel p.53
- Rec Warehouse (OEM 303909, M-4326) Unicel p.53
- River Valley Spas Unicel p.54
- Royal Spas Unicel p.54
- Rubadub Tub Unicel p.54
- Safari Spas Unicel p.54
- Signature Spas Unicel p.55
- Spa Manufacturers Inc. Unicel p.56
- Streamline Spas Unicel p.58
- Sun Ray Spas (Canada) Unicel p.58
- Thermo Spas of Connecticut Unicel p.60
- US Spas Unicel p.62
- Viking Spas Unicel p.63
- Waters Edge Spas Unicel p.63
- Waterway Plastics (models: Top load (in-line) 25 sq.ft., TWM Cartridge Filter Pack; OEM 817-2500, M-4326) Unicel p.64
- Zone Spas Unicel p.65
FAQ
What is the Unicel equivalent of Pleatco PRB25-IN?
The catalogs cross-reference Pleatco PRB25-IN to Unicel C-4326.
What is the Filbur equivalent of Pleatco PRB25-IN?
The catalogs list Filbur FC-2375.
What size is the PRB25-IN filter?
Pleatco lists PRB25-IN as 5" outside diameter by 13-5/16" long, top: 2-1/8" open, bottom: 2-1/8" open, 25 sq ft.
Which OEM part numbers does it replace?
Listed OEM numbers: 17-2327, 100586, 33521, 25392, 303909, M-4326, 817-2500, R173429, 3005845, 3301-2242, 373045, 2501.
Sources: Filbur Product Catalog and Reference Guide (2024) · Pleatco 2023 Catalog & Cross Reference Guide (Pentair) · Pleatco 2023 Catalog & Cross Reference Guide (Pentair) · Pleatco 2023 Catalog & Cross Reference Guide (Pentair) · Unicel 2026 Replacement Guide. Last checked 2026-10-21.