Pleatco Spa Filter Cartridge PRB25-IN Replacement for Unicel C-4326 Filbur FC-2375 — 25 sq ft, Point-Bonded Media

Pleatco PRB25-IN is a high-performance replacement spa filter cartridge engineered to fit Unicel C-4326 and Filbur FC-2375 applications while improving water clarity and reducing maintenance.

This genuine Pleatco cartridge combines advanced point-bonded media with a reinforced free-flow core to capture finer particles, sustain higher flow rates, and extend the time between cleanings. Manufactured and quality-tested in the U.S., the PRB25-IN matches OEM dimensions for a direct swap and offers features designed to lower operating pressures on pump systems and make cleaning easier.

How does this cartridge improve spa water clarity?

The PRB25-IN uses Pleatco's point-bonded filtration fabric that traps smaller contaminants compared with standard media. That finer capture means clearer, cleaner water and less frequent filter cleanings without changing your equipment setup.

• Advanced point-bonded media with high fiber density for finer filtration
• 25 square feet of media surface area to hold more debris
• Even dirt-loading design prevents localized clogging

Will this filter fit my existing spa system?

The PRB25-IN is a direct replacement for Unicel C-4326 and Filbur FC-2375 and is compatible with many Dynamic and Waterway in-line models. Its critical dimensions match OEM specs so installation is straightforward: same top and bottom hole diameters and length.

• Diameter: 5" (127 mm); Length: 13.3125" (338.14 mm)
• Top and bottom hole size: 2.125" for direct fit
• Compatible cross-references listed by Pleatco for easy verification

What design elements reduce pump strain and maintenance?

Pleatco's Free Flow Core features a box-ladder injection-molded structure that reinforces the cartridge and promotes consistent water flow across the media. Greater flow and lower operating pressure reduce wear on pumps and help the media load dirt evenly, extending service life.

• Injection-molded core supports higher flow with less pressure
• Reinforcing supports maintain pleat spacing and stability
• Superbond bands resist breakage and simplify cleaning

How easy is it to clean and maintain this filter?

The point-bonded fabric releases trapped debris quickly during routine rinsing, which shortens cleaning time and lowers the effort required. Regular rinses and occasional deep-soak cleanings will restore flow and keep the cartridge functioning near peak performance.

• Media formulated to release dirt with simple rinsing
• Longer cycles between required cleanings compared with conventional cartridges
• SmartTrack code printed for lifetime identification and support

Who is this for: Owners and service technicians who need an OEM-fit, high-efficiency spa filter that reduces maintenance frequency and lowers operating strain on pumps. The Pleatco PRB25-IN is ideal for anyone replacing Unicel C-4326 or Filbur FC-2375 cartridges, or for users seeking a durable upgrade with documented quality controls and U.S.-based engineering support.