Free standard shipping · a compatible part that fits your model — or we pay the return
PartFit
preview build
Model⁠×⁠filter compatibility · 51 models · 50 parts · verified 2026-07-03

Home / Find my part / Universal 25 sq ft drop-in spa cartridge (PRB25-IN)

Parts for your model

Replacement parts for the Universal 25 sq ft drop-in spa cartridge (PRB25-IN)

The exact compatible parts we've verified fit this model. Guaranteed fit

BrandUniversal
Model25 sq ft drop-in spa cartridge (PRB25-IN)
Typical useEntry hard-shell hot tubs — DROP-IN, 25 sq ft (authoritative Unicel = C-4326)
Also known asPRB25-IN, C-4326, FC-2375, 817-2500, R173429, C-4625

Compatible parts

Check a different model →   Remind me when it's due →

FAQ

What replacement filter fits the Universal 25 sq ft drop-in spa cartridge (PRB25-IN)?

It uses 817-2500 / R173429 (Replacement Spa Cartridge — Compatible with Pleatco PRB25-IN / Unicel C-4326 / Filbur FC-2375 (25 sq ft drop-in)). Our compatible version matches that fit and carries a fit guarantee.

How often should I change the part on a Universal 25 sq ft drop-in spa cartridge (PRB25-IN)?

Typical replacement is Change every 4 months, sooner in dusty or pet homes.