Pleatco PRB35-IN = Unicel C-4335 = Filbur FC-2385
35 sq ft hot tub filter, 5" diameter × 9-1/4" long. Top: 2-1/8" open · Bottom: 2-1/8" open. Pleatco application: Dynamic Series IV - DFM, DFML, Waterway 35, In-Line.
Interchangeable cartridges
- Unicel C-4335 confirmed by: Pleatco p.47 (Unicel to Pleatco cross reference) Unicel p.8 (Cartridges by series (dimensional listing))
- Filbur FC-2385 confirmed by: Pleatco p.48 (Filbur to Pleatco cross reference) Filbur p.33 (Reverse cross reference (Unicel to Filbur)) Filbur p.9 (Dimensional cartridge listing)
Published dimensions, side by side
Each manufacturer measures a little differently. Compare these with your old cartridge.
| As published by | Pleatco PRB35-IN source | Unicel C-4335 source | Filbur FC-2385 source |
|---|---|---|---|
| Outside diameter | 5" | 4-15/16" | 4-15/16" |
| Length | 9-1/4" | 9-1/4" | 9-1/4" |
| Top end | 2-1/8" open | 2-1/8" / open | 2-1/8" open |
| Bottom end | 2-1/8" open | 2-1/8" / open | 2-1/8" open |
| Filter area | 35 sq ft | 35 sq ft | 35 sq ft |
| Pleats | not listed | 219 | not listed |
| Media weight | 3 oz/yd² | 3 oz/yd² | not listed |
Where to buy
Search any retailer for C-4335 or PRB35-IN or FC-2385. 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.
- Aber Hot Tubs (Canada) (OEM 03FIL1300) Unicel p.26
- Belize Spas Unicel p.29
- Bullfrog Spas Unicel p.30
- Caldera Spas (OEM 74148) Unicel p.30
- Clearwater Spas Unicel p.31
- Coast Mountain Spas (Canada) Unicel p.31
- Columbia Spas Unicel p.32
- Crystal Waters Spas (Canada) Unicel p.32
- Custom Molded Products (models: Top Mount Skim, EZ Twist Top Mount Skim, Top Load Pressure; OEM 25393) Unicel p.33
- Emerald Spas Unicel p.35
- Great Lakes Home & Resort Unicel p.36
- Gulf Coast Spas Unicel p.36
- Hawkeye Spas Unicel p.37
- Hydro Pool Industries Unicel p.39
- Hydro Spa Unicel p.39
- Infinity Spas - TN Unicel p.40
- Moose Mountain Spas (Canada) Unicel p.45
- Orca Bay Spas (OEM 3501) Unicel p.46
- Pentair Pool Prod (models: Dynamic Series IV - DFM,DFML; OEM R173431) Unicel p.47
- Pentair Pool Prod - Rainbow Plastics (models: Dynamic Series IV - DFM,DFML; OEM 17-2482) Unicel p.52
- Phoenix Spas Unicel p.53
- Premium Leisure Unicel p.53
- Rec Warehouse (OEM 303557) Unicel p.53
- Sun Coast Spas Unicel p.58
- Sun Ray Spas (Canada) Unicel p.58
- Sundance Spas (models: Tacoma 680; OEM 6000-136) Unicel p.59
- Sunrise Spas Unicel p.59
- Waterway Plastics (models: Top load (in-line) 35 sq.ft.; OEM 817-3501) Unicel p.64
- Wind River Spas Unicel p.65
FAQ
What is the Unicel equivalent of Pleatco PRB35-IN?
The catalogs cross-reference Pleatco PRB35-IN to Unicel C-4335.
What is the Filbur equivalent of Pleatco PRB35-IN?
The catalogs list Filbur FC-2385.
What size is the PRB35-IN filter?
Pleatco lists PRB35-IN as 5" outside diameter by 9-1/4" long, top: 2-1/8" open, bottom: 2-1/8" open, 35 sq ft.
Which OEM part numbers does it replace?
Listed OEM numbers: 03FIL1300, 17-2482, 25393, 303557, 817-3501, 74148, 3501, R173431, 6000-136.
Sources: Filbur Product Catalog and Reference Guide (2024) · 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.