Unicel Replacement Filter Cartridge 150 sf Waterway | C-9403

Unicel SKU: C-9403
Unicel Replacement Filter Cartridge 150 sf Waterway | C - 9403 - Cartridges - img - 1

Unicel Replacement Filter Cartridge 150 sf Waterway | C-9403

Unicel SKU: C-9403
  • In stock, ready to ship
  • Inventory on the way
$119.99
Instant Savings: $40
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Questions about returns? View our return policy.
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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

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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.
Questions about returns? View our return policy.

Hours Of Operation:

Monday - Friday: 7:00 am to 5:00 pm Phoenix Time

Saturday: 8:00 am to 2:00 pm

Sunday: Closed

  • We do not ship on Saturday or Sunday.
  • Orders totaling more than $300 will require signature confirmation upon delivery.
  • We process and prepare orders for shipment within 1 business day. Please note that many other pool supply retailers require 3–5 days of handling time before shipping.
  • Orders placed after 1:00 pm Phoenix Time may not be eligible for same-day shipment.
  • Expedited shipping options are available at checkout.

Return Policy:

  • Products that are received damaged will receive a refund in store credit.
  • Most products are eligible for return within 30 days of receipt, except where noted below.
  • To initiate a return, please complete an RMA form prior to sending your item back.
  • Original shipping costs are non-refundable and will be deducted from the return credit.
  • Items returned missing accessories or original packaging, or that are not in the same condition as received, may be subject to a restocking fee of up to 100% depending on the condition of the item upon return.
  • Some returns will be charged an automatic 15% restocking fee.
  • We are unable to issue refunds for items that have been damaged or rendered inoperable due to installer error.
  • Please complete the return form to receive your RMA number and return shipping label.
  • Chemical products are not eligible for return under any circumstances.
  • The Pentair Colorsync 618031 is not eligible for return.
  • Pool cleaners are not eligible for return.
  • Opened seals and o-rings are not eligible for return.
  • Capacitors are not eligible for return.
  • Plastic popup tools are not eligible for return.
  • Automation components and circuit boards are not eligible for return.
  • If a light is returned due to a reported malfunction and is found to be fully operational upon testing, return shipping costs and a restocking fee will be deducted from the refund.
  • Orders refused at the time of delivery will be subject to the original shipping costs being deducted from the refund.
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