Unicel C-4305 Hot Tub Filter Cartridge

The Unicel C-4305 has been used in a variety of hot tub models and brands over the years, including select Cal Spas and the 1994 Suntub by Sundance Spas. As filter dimensions can vary between spa models, it’s always best to confirm this cartridge matches the size of your existing filter to ensure proper fit and performance.

Specifications:

• Part Number: C-4305

• Diameter: 4-15/16"

• Length: 14-7/8"

• Top: 2-1/8" Open

• Bottom: 2-1/8" Open

• Media Area: 50 sq. ft.

• Filter Media: 3 oz. Reemay® premium trilobal fabric

• Pleat Count: 193

Compatible Replacements:

• Pleatco PMT50

• Filbur FC-1630

• Martec CL-2807, CL-2810

• Sonfarrel 220142, 220145, 220152

• Sundance 6540-497 (1994 Suntub only)

Long-Lasting Performance:
While most spa filters require replacement every 6–12 months, the Unicel C-4305 uses Reemay® premium trilobal filtration media, which provides 45% more surface area than standard rounded fibers. With proper cleaning and maintenance, it can last up to 18 months or more, depending on usage and care routine.