FROG 01-14-3712 Filter Mate Spa Mineral Sanitizer: The mineral sanitizer that cleans and softens hot tub water inside your filter cartridge. While you’ll add dichlor or bromine separately, you’ll need half the usual amount, because our FROG minerals are active sanitizers. The result is you kill bacteria two ways – with minerals and a low level of chlorine or bromine. We call it Fresh Mineral Water® because it looks and feels amazing.