Alcove hot tub filters
The Unicel 2026 Replacement Guide lists 1 of the cartridges on this site for Alcove. 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 | Alcove OEM # | Source |
|---|---|---|---|---|---|
| PTL18P4 / 4CH-21 / FC-0121 | 4-5/8" x 8" | 18 | not specified | not listed | Unicel p.26 |
If your Alcove filter isn't here, it may not be in our checked list yet. We only publish matches we can confirm in a manufacturer catalog.