Hydro Spa hot tub filters
The Unicel 2026 Replacement Guide lists 4 of the cartridges on this site for Hydro Spa. Many tubs use only one of these, so measure your old filter or check the number printed on its end cap.
| Cartridge (Pleatco / Unicel / Filbur) | Diameter × length | Sq ft | Models | Hydro Spa OEM # | Source |
|---|---|---|---|---|---|
| PGS25P4 / 4CH-24 / FC-0131 | 4-5/8" x 9-3/4" | 25 | not specified | not listed | Unicel p.39 |
| PRB35-IN / C-4335 / FC-2385 | 5" x 9-1/4" | 35 | not specified | not listed | Unicel p.39 |
| PTL47W-P4 / 6CH-47 / FC-0315 | 6" x 8-1/2" | 47 | not specified | not listed | Unicel p.39 |
| PRB50-IN / C-4950 / FC-2390 | 5" x 13-5/16" | 50 | not specified | not listed | Unicel p.39 |
If your Hydro Spa filter isn't here, it may not be in our checked list yet. We only publish matches we can confirm in a manufacturer catalog.