Unicel 6CH-26 Replacement Spa Filter Cartridge – 25 Sq Ft (6″ OD, Handle Top, 1-1/2″ Threaded Bottom)
The Unicel 6CH-26 is a 25 sq ft pleated replacement filter cartridge used in select hot tub and spa filtration systems that require a compact top-load cartridge with a semi-circular handle and a 1-1/2″ threaded bottom connection. Replacing a worn cartridge helps restore circulation, improves water clarity, and reduces strain on spa pumps and heaters.
Key Features
- 25 sq ft filtration area for dependable debris capture
- Top: semi-circular handle for easy removal
- Bottom: 1-1/2″ male threaded connection (commonly listed as MPT / SAE coarse thread depending on catalog)
- Durable pleated media designed for repeated rinsing and deep-clean cycles
- Direct replacement when matched by part number and dimensions
Specifications
- Part Number: 6CH-26
- Filtration Area: 25 sq ft
- Outside Diameter: 6″
- Length: 7″ (some catalogs list approximately 7-1/8″)
- Top End Cap: Closed with handle
- Bottom End Cap: 1-1/2″ male threaded
Replaces / Cross References (Verify Fit)
- Filbur: FC-0310
- Pleatco: PAT25P4 (also commonly referenced: PTL25W-SV-P-4)
- Other common references: 12521, AK-9012
Compatibility Notes
- Many spa cartridges look similar—confirm the 6″ OD, ~7″ length, handle top, and 1-1/2″ threaded bottom before ordering.
- If your current filter has a slip fitting (non-threaded) bottom, a different thread size, or a different top style, you likely need another model.
When to Replace
- Flow is weak or the system struggles to maintain circulation even after cleaning
- Pleats are torn, frayed, flattened, or separating from the end caps
- Filter quickly plugs again after rinsing
- End caps or threaded connection are cracked/warped and won’t seal properly
Related Products
- Unicel 6CH-26 (Shop / Options)
- Spa Cartridge Filter Cleaner
- Cartridge Cleaning Wand
- Spa Water Test Strips
- Spa Scale Remover
- Spa Fill / Hose Pre-Filters
Maintenance Tips
- Rinse the cartridge regularly (often weekly with heavy use) to prevent restriction and keep flow strong.
- Deep clean every 3–6 weeks with a cartridge cleaner to remove oils; rinse thoroughly before reinstalling.
- If scale is present, degrease first, then treat for scale (never reverse the order), and rinse completely.
- Rotating between two cartridges (one in use, one drying after cleaning) can extend filter life and improve performance.
