Bullfrog spa filter (C-4335)

Bullfrog Spas

Replacement numbers

Unicel C-4335, Pleatco PRB35-IN

Fits Bullfrog Spas.

Diameter 4-15/16" (125 mm)Length 9-1/4" (235 mm)35 sq ft

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UnicelC-4335
PleatcoPRB35-IN
FilburFC-2385
Top2-1/8" (54 mm) / open
Bottom2-1/8" (54 mm) / open
Ø 4-15/16" (125 mm)9-1/4" (235 mm)Side view · end views belowTopBottom
Top: 2-1/8" (54 mm) / open
Bottom: 2-1/8" (54 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. 35 sq ft media.

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For Bullfrog, C-4335 cartridge sits in Bullfrog Spas. The cross-reference prints Unicel C-4335; Pleatco PRB35-IN; Filbur FC-2385. 4-15/16" across, 9-1/4" long, top 2-1/8" / open, bottom 2-1/8" / open, 35 sq ft.

C-4335 is easy to confuse on the Bullfrog table. PBF17 differs by no Unicel number, Pleatco PBF17, no Filbur number, 6-5/8" diameter, 6-1/4" long, top 3-3/8" open (coreless), bottom 4-1/2" open (coreless), 18 sq ft, OEM 10-00281, note says Pleatco: Bullfrog 18 coreless, 2017-current. Leisure Time Inc. rates the OEM 10-00281 cartridge at approximately 27 sq ft and notes 2015-2017 STIL spas need Filter Core Cage & Cap Assembly 10-00417; Leisure Time Inc.: Coreless cartridge; the correct filter cage and cap must be installed.. PBF40 differs by no Unicel number, Pleatco PBF40, no Filbur number, 8" diameter, 6-1/4" long, top 3-3/8" open (coreless), bottom 4-1/2" open (coreless), 30 sq ft, OEM 10-00282, note says Pleatco: Bullfrog 30 coreless, 2017-current. Leisure Time Inc. rates the OEM 10-00282 cartridge at 50 sq ft and notes 2013-2017 A/R/X spas need the Filter Core Cage & Cap Assembly; 2023-and-newer A Series use Simplicity flat filters; Leisure Time Inc.: Coreless cartridge; the correct filter cage and cap must be installed. 2023-and-newer A Series models use Simplicity flat filters..

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

Source locations for this Bullfrog row: Unicel 2026 Replacement Guide on C-4335 (OEM cross reference (Bullfrog section), PDF p.30 (printed p.26); spec table PDF p.8 (printed p.4)). Pleatco 2023 Catalog on C-4335 (Unicel-to-Pleatco cross reference, PDF p.47). Filbur Catalog & Reference Guide on C-4335 (Product by Pool/Spa Manufacturer (OEM), Bullfrog, printed p.29 (PDF p.15)).

If you know the Bullfrog model and not the part number, use the Bullfrog 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: Bullfrog filters. Number formats: how Filbur, Unicel and Pleatco numbers compare.

The same C-4335 number is also on the Caldera, Sundance pages.

Other Bullfrog cartridges

All 7 Bullfrog 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 model/model-year fitment in sources; Unicel lists no OEM part number for this brand entry.