Filters for Apollo Spas

Filters for Apollo Spas

Three main filter cartridges are used in Apollo Spas. Thse are:

Pleatco PRB17.5SF PR/ Unicel C-4401 - this cartridge measures 4 5/8" long x 4 15/16" in diameter, and two filters togetherhave an area of 35 square feet on the pleats.

Pleatco PRB25-1N / Unicel C-4326 - this cartridge measures 13 5/16" long with a diameter of 4 15/16, and 2 1/8" ID holes at each ends. The overall area is 25 square feet.

Pleatco PRB50-1N / Unicel C-4950 - this cartridge measures 13 5/16" long with a diameter of 4 15/16", and 2 1/8" ID holes at each end. The overall area is 50 square feet.

Please check the filter cartridge requirements for your hot tub - if it has been fitted with 25 sq.ft filter cartridges and you feel that the water quality is not wonderful, check the chemical balance and see if it should be fitted with the PRB 50, which has twice the filter area - but the same physical dimensions, due to bigger pleats.