Hot Springs MPS is a non chlorine spa shock (oxidizer) used to effectively reduce odor-causing ammonia and chloramines as well and soaps and oils. The result will be fresher, clearer, odor-free water. Hot Springs MPS Oxidizer is not a disinfectant and should be used in addition to ozone, chlorine or bromine. It is recommended that you shockyour spa once a week or for every hour of use, which ever is greater.