Unicel C-8465 Hot Spring Spa Filter – 65 Sq Ft | FC-3960 & PWK65

Unicel C-8465 Replacement Spa Filter Cartridge — 65 Sq. Ft.

The Unicel C-8465 is a premium 65-square-foot replacement spa filter cartridge designed for select Hot Spring Spas, Tiger River Spas, Watkins Manufacturing spas, and certain Caldera Spa applications. Unicel upgraded this cartridge from the original 45-square-foot design to 65 square feet of filtration area with 234 pleats, providing enhanced filtration performance while maintaining proper water flow through your spa system.

Its 3 oz. filtration media helps capture dirt, body oils, debris, and other contaminants to keep your spa water clean and clear. Customers searching for Filbur FC-3960, Pleatco PWK65, Watkins/Hot Spring OEM 31114, Hot Spring OEM 71827, Watkins OEM 71828, or Caldera OEM 76136 may find this to be the compatible replacement.

Key Features

• Genuine Unicel C-8465 replacement spa filter
• 65 sq. ft. filtration area — upgraded from the original 45 sq. ft. design
• 234 pleats for thorough water filtration
• 3 oz. filtration media
• 8-1/2" outside diameter
• 10-1/2" length
• 3" open top
• 3" open bottom
• Designed for select Hot Spring / Watkins spa applications
• Cross-references FC-3960 and PWK65

Specifications

• Manufacturer: Unicel
• Part Number: C-8465
• Filter Area: 65 sq. ft.
• Outside Diameter: 8-1/2"
• Length: 10-1/2"
• Pleat Count: 234
• Filter Media: 3 oz. filtration media
• Top End: 3" open
• Bottom End: 3" open

Cross-Reference / Replacement Part Numbers

Customers searching for any of the following part numbers may find this to be a compatible replacement:

• Unicel: C-8465
• Filbur: FC-3960
• Pleatco: PWK65
• Watkins / Hot Spring OEM: 31114
• Hot Spring OEM: 71827
• Watkins OEM: 71828
• Caldera OEM: 76136

Compatibility & Fitment

The Unicel C-8465 is used in select Watkins-family spas including Hot Spring Spas, Tiger River Spas, and certain Caldera Spa applications. Fitment varies by model and year.

Before ordering, please compare your existing filter’s part number and verify the following dimensions match:

• Outside diameter: 8-1/2"
• Length: 10-1/2"
• Top end: 3" open
• Bottom end: 3" open

Note: The current Unicel C-8465 replacement cartridge is rated at 65 sq. ft. and is an upgrade over the original 45 sq. ft. filter design.

Why Buy From Red Rock Spas?

Red Rock Spas specializes in hot tubs, replacement spa filters, spa parts, and water-care products. If you’re unsure whether the Unicel C-8465 is the correct filter for your spa, our team can help you identify the right replacement — just reach out before ordering.