The Unicel C-9403 is a replacement pleated cartridge filter element designed for select pool and spa cartridge filter canisters. It captures fine debris to help keep water clear while maintaining strong circulation when cleaned and serviced regularly.
Key Features
Replacement cartridge filter element for compatible filter housings
Pleated media increases surface area for effective particle capture
Helps support steady flow when kept clean (less strain on the pump vs. a clogged cartridge)
Durable end caps and core for repeated cleaning cycles
Before You Buy
Match by part number (C-9403) whenever possible.
Confirm fit by measuring your existing cartridge:
Overall length
Outside diameter
Top and bottom end-cap style (open, closed, handle, or threaded)
Inside diameter of any open ends
If your filter uses an internal standpipe, verify the cartridge’s inside opening matches the standpipe size and style.
Common Signs It’s Time to Replace
Pleats are torn, frayed, or separating from the end caps
Cartridge won’t clean up well even after a deep soak and thorough rinse
Filter pressure rises quickly after cleaning or circulation remains weak
End caps are cracked, warped, or the core is collapsing
Related Products
Cartridge Filter Cleaner
Cartridge Cleaning Tools
Filter Tank O-Rings & Gaskets
Filter Pressure Gauges
Skimmer Socks (Fine Debris Pre-Filter)
Maintenance Tips
Rinse the cartridge when pressure rises about 8–10 PSI above your clean starting pressure (or when flow drops).
Spray between pleats from top to bottom and rotate as you clean to remove trapped debris.
Deep clean periodically to remove oils and scale; rinse thoroughly before reinstalling.
Let the cartridge dry after deep cleaning when possible—drying helps loosen fine debris for easier rinsing.
Keep water chemistry balanced to reduce premature clogging and scale buildup.
