As noted in the Nature2 manual linked to above, the "low chlorine" recipe uses non-chlorine shock (potassium monopersulfate aka MPS) as the disinfectant and oxidizer (MPS is a disinfectant only when used with the silver ions in Nature2 at hot spa temperatures). With an ozonator, you may only need to add around 3 teaspoons of MPS for every person-hour of soaking.
MPS is fairly acidic so you'd keep your Total Alkalinity (TA) up higher to help the pH be more stable. If you need to raise the pH, you can use pH Up (sodium carbonate) though that also raises the TA more, or you can use 20 Mule Team Borax which raises the TA only half as much. If you need to lower the pH, you can use dry acid.