Unicel Replacement Filter Cartridge 150 sf Waterway | C-9403

Unicel C-9403 Replacement Cartridge Filter

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.