Unicel 7CH-552 Replacement Filter Cartridge | 52 sq. ft. | Dimension One Spas PS3868 The S7D75 requires 2 grids

The S7D75 requires 2 grids

A good starter mix is one gallon of acid added to two gallons of water

this is the stainless steel 304

Do NOT test if your pool water is below 65F

Unicel 7CH-552 Replacement Filter Cartridge | 52 sq. ft. | Dimension One Spas PS3868 The S7D75 requires 2 gridsThe Unicel 7CH 552 is a 7000 Series 52 sq. ft. replacement filter cartridge engineered specifically for Dimension One Spas filtration systems. Built on 3 oz. Reemay 2033 polyester media with 216 precision pleats, it delivers maximized surface area in a compact 10 1 2" body keeping your spa water clean and clear between services. The 2" male thread bottom fitting threads directly into your filter standpipe for a secure, leak free connection.