POOLPURE Spa Filter Cartridge PRB25SF Replacement for Unicel C-4405 / Filbur FC-2387 — 6-5/8" x 5", 50‑Micron Trilobal

POOLPURE PRB25SF is a heavy-duty replacement spa cartridge engineered to restore clear, debris-free water for spa and small pool systems that use Unicel C-4405 / Filbur FC-2387 style filters.

Built with a trilobal filtration fabric, reinforced cores and a 50-micron media layer, this POOLPURE replacement cartridge balances high-efficiency particle capture with easy rinsing and long service life. It’s designed as a compatible swap for common OEM part numbers and tested in demanding aquatic environments; the result is consistent clarity and fewer cartridge changes over the season.

How does this filter improve water clarity?

The PRB25SF combines a trilobal fiber structure with a fine 50-micron layer to trap very small particles that standard filters miss. That dual-action design increases surface area and holds more debris between cleanings, so water looks clearer longer without extra chemicals.

• Trilobal fabric delivers roughly three times the adsorption surface compared to ordinary fibers
• 50-micron filtration captures hair, dust, sand, and fine organic matter
• 50 sq. ft. filtration area reduces flow restrictions while maximizing capture

Will this cartridge fit my existing spa or pool system?

The PRB25SF is a direct compatible replacement for several common OEM part numbers, including Unicel C-4405 and Filbur FC-2387, and matches the same critical dimensions for drop-in swap. Confirm your unit’s length and end-cap opening measurements before ordering to ensure a correct fit.

• Length: 6 5/8" and outer diameter: 5" for direct compatibility
• Top and bottom openings: 2 1/8" to match standard housings
• Listed cross-reference: Unicel C-4405, Filbur FC-2387, R172464 and others

How does cleaning and maintenance compare to other cartridges?

POOLPURE’s patented dirt-locking fabric releases trapped debris easily during a rinse, so maintenance is quicker and more effective. The reinforced construction resists wear and wrinkles, meaning you’ll rinse fewer times and replace cartridges less often than standard models.

• Patented dirt-locking structure simplifies rinse-clean cycles
• 4 oz. thickened polyester fabric and reinforced ABS end caps improve durability
• Reusable with routine rinsing; longer lifespan reduces replacement frequency

Is the product safe and industry certified?

Yes — components used in this POOLPURE cartridge are tested for long-term water exposure and meet NSF/ANSI 50 material safety standards, assuring you won’t introduce harmful substances into your water. POOLPURE also partners with recognized industry groups and aquatic programs to validate performance in real-world conditions.

• IAPMO-tested to NSF/ANSI 50 for material safety
• PHTA membership and athlete-tested performance in training environments
• Used and recommended by trained pool professionals and competitive aquatic programs

Who is this for? The POOLPURE PRB25SF suits spa and small-pool owners who want a high-efficiency, long-lasting replacement cartridge compatible with common OEM numbers. It’s ideal for homeowners and facility managers seeking stronger fine-particle capture, reduced maintenance time, and a durable cartridge that holds up under frequent use.