Unicel 4CH-925 Replacement Spa Filter Cartridge – 20 Sq Ft (4-5/8″ OD x 7-1/4″ Length, 1-1/2″ SAE Thread)
The Unicel 4CH-925 is a top-load spa filter cartridge designed for select hot tubs and spa filter canisters that use a 1-1/2″ SAE threaded (screw-in) bottom connection. It uses durable pleated media to capture fine debris for clearer water and more consistent flow when rinsed and cleaned on a regular schedule.
Key Features
- 20 sq ft filtration area for effective spa water polishing
- Bottom: 1-1/2″ SAE screw-in thread for a secure fit in compatible housings
- Top: handle-style end cap for easy removal
- Replaces worn or damaged cartridges to help restore circulation and water clarity
- Built for repeated rinse and deep-clean cycles
Specifications
- Part Number: 4CH-925
- Filtration Area: 20 sq ft
- Outside Diameter: 4-5/8″ (4.625″)
- Length: 7-1/4″ (7.25″)
- Top End Cap: Handle (closed)
- Bottom End Cap: 1-1/2″ SAE thread (injection molded)
- Pleat Count: 190
- Media: 3 oz pleated media
Replaces / Cross References
- Pleatco: PSANT20P3
- Filbur: FC-0126
- Darlly: 42524
- Baleen: AK-90083
Compatibility Notes
- Designed for spa filter canisters that require a 1-1/2″ SAE screw-in cartridge with a 4-5/8″ diameter body.
- Often used in select spa brands such as Strong, Softsider, and Futura (verify by measurements and thread style).
- Always confirm fit by matching the OD, length, and bottom thread type to your existing cartridge.
When to Replace
- Pleats are torn, frayed, flattened, or separating from the end caps
- Flow is weak or the system struggles to maintain circulation even after cleaning
- Water stays cloudy despite balanced chemistry and normal sanitizer levels
- End caps or the threaded connection are cracked/warped and won’t seal properly
Related Products
- Spa Cartridge Filter Cleaner
- Cartridge Cleaning Wand
- Spa Water Test Strips
- Spa Fill / Hose Pre-Filters
- Silicone O-Ring Lubricant (Pool/Spa)
Maintenance Tips
- Rinse the cartridge frequently (often weekly with regular spa 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 overall filter life and improve filtration.
