Abstract: A mixing system for introducing ozone into water of a hydrotherapy spa includes filter for filtering water from said hydrotherapy spa. A pump draws water from said hydrotherapy spa through said filter. A first injector includes a first input for receiving filtered water from said filter, a second input for receiving ozone, and an output for providing a first mixture of ozone in solution with said filtered water and ozone not in solution with said filtered water. A recapturing unit, coupled to said output of said first injector, separates said ozone not in solution with said filtered water from said first mixture. A second injector, having a first input coupled to said recapturing unit, a second input coupled to said filter, and an output, provides a second mixture of said ozone not in solution with said filtered water and said filtered water at said output of said second injector means.