Unicel Replacement Filter Cartridge 45 sf | C-5345
Unicel
SKU: C-5345
Unicel C-5345 Replacement Spa Filter Cartridge – 50 Sq Ft (Marquis / “String Handle” Style)
The Unicel C-5345 is a high-quality 50 sq ft pleated spa filter cartridge commonly used in select Marquis Spas and other hot tub filtration systems that use a closed top with a string handle. Replacing a worn cartridge helps restore circulation, improves water clarity, and reduces strain on the spa pump and heater.
Key Features
- 50 sq ft filtration area for strong debris capture and steady spa flow
- Closed top with string handle for easy removal during cleaning
- Open bottom design for compatible standpipe/canister connections
- Durable pleated media and rigid inner core built for repeated cleanings
Specifications
- Part Number: C-5345
- Filter Type: Pleated spa cartridge
- Filtration Area: 50 sq ft
- Top End Cap: Closed (string handle)
- Bottom End Cap: Open
- Common Size Class: 50 sq ft “string-handle” style cartridge (confirm measurements before ordering)
Compatibility Notes
- Used in select Marquis and similar spa filter canisters that take a 50 sq ft cartridge with a string handle top.
- Best practice: match by part number and verify your existing cartridge’s outside diameter, length, and bottom opening (ID).
- If your current filter is close in appearance but a different height or bottom opening, choose the cartridge that matches your exact measurements.
When to Replace
- Pleats are torn, frayed, or separating from the end caps
- Cartridge remains restrictive even after a thorough rinse and deep clean
- Water stays cloudy despite balanced chemistry and proper sanitizer levels
- End caps are cracked/warped or the inner core is collapsing
Related Products
- Unicel C-5345 (Shop / Options)
- Spa Cartridge Filter Cleaner
- Cartridge Cleaning Wands
- Spa Water Test Strips
- Spa Scale Remover
- Silicone O-Ring Lubricant (Pool/Spa)
Maintenance Tips
- Rinse the cartridge regularly (often weekly with heavy spa use) to prevent restriction and cloudy water.
- Deep clean every 3–6 weeks using 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 performance.
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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