Home › Caldera › C-4335 cartridge (OEM 74148)
Caldera OEM 74148 spa filter (C-4335)
Listed for: Caldera (Watkins)
Fits Caldera OEM 74148 cited
Ø 4-15/16"L 9-1/4"35 sq ft| Unicel | C-4335 |
|---|---|
| Pleatco | PRB35-IN |
| Filbur | not sourced |
| Top | 2-1/8" / open |
| Bottom | 2-1/8" / open |
Retailer search links — see disclosure. Verify dimensions before ordering.
How to confirm this is your filter
Pull your current cartridge and measure it end to end, including any handle, and across the widest point of the pleats. This cartridge measures 4-15/16" in diameter and 9-1/4" long, with a 2-1/8" / open on top and a 2-1/8" / open on the bottom. The bottom fitting matters most: a cartridge with the right diameter but the wrong thread or open-end size will not seal in the filter housing, letting unfiltered water bypass the media.
The 35 sq ft rating describes the pleated media area. Caldera housings are designed around a particular cartridge, so choose a replacement with the same size and fittings rather than a larger area rating. Unicel C-4335 and Pleatco PRB35-IN are cross-referenced to each other in the Pleatco 2023 catalog, so either should fit the same housing.
Similar-diameter Caldera cartridges
- C-4950 cartridge (OEM 302005) — 4-15/16" × 13-5/16"
Sources
- Unicel 2026 Replacement Guide — OEM Cross Reference, PDF p.29; spec table PDF p.7 (PDF)
- Pleatco 2023 Catalog — Unicel-to-Pleatco cross reference, PDF p.43 (PDF)
Not in sources: no Filbur equivalent sourced; no model-year range in source.