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817-2500 spa filter equivalents
Part number 817-2500 appears in 1 cross-reference row below. Each row lists the OEM, Unicel and Pleatco numbers that the source documents treat as interchangeable, plus the cartridge size so you can confirm against your old filter.
The same numbers, on one page, are in the cross-reference lookup. A schedule for this part number, and the buy link, are on the replacement schedule and reorder page. Published intervals by brand are in the replace and clean calculator.
Waterway Plastics C-4326 cartridge (OEM 817-2500), 4-15/16" (125 mm) × 13-5/16" (338 mm), 25 sq ft. Unicel C-4326, Pleatco PRB25-IN.
Unicel C-4326
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| OEM | 817-2500 |
|---|---|
| Unicel | C-4326 |
| Pleatco | PRB25-IN |
| Filbur | FC-2375 |
| Size | 4-15/16" (125 mm) × 13-5/16" (338 mm), 25 sq ft |
Sources
- Unicel 2026 Replacement Guide: Waterway list PDF p.64: 817-2500 = C-4326, 4-15/16" x 13-5/16", 25 sq ft. Spec table PDF p.9: open 2-1/8", 106 pleats. (PDF)
- Waterway Plastics Service Logic cartridge table: Fetched 2026-11-09: 817-2500, 25 sq ft, in-line top-load (web page)
- Pleatco 2023 Catalog: Spec table PDF p.32: PRB25-IN includes OEM 817-2500, 5" x 13-5/16", 25 sq ft (PDF)
- Filbur Catalog & Reference Guide: Waterway section PDF p.28: FC-2375 and FC-2910 both list OEM 817-2500. Size table lengths FC-2910 at 13-1/4". (PDF)
Not in sources: Outside diameter 4-15/16" vs Pleatco 5". Filbur FC-2910 length 13-1/4" in the size table and 12-1/4" in the Waterway section, against 13-5/16" on FC-2375, Unicel, and Pleatco..
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