For the record, my experience is that constant ozone generation (and resulting O2 injection) in showroom tubs tends result in pH higher than the spas in the same showroom, using the same chemicals with 2*3 hour ozonation.
Customers that do not turn off there air controls (in non circ pump tubs) tend to have higher pH than those that do not. This is because injection of air results in pH creep.
I know that is far from scientific data, just my experience.
I know your experience in the industry far exceeds mine, but upon what do you base your statement above if I may ask?
Ozone is in fact pH neutural, that being the case it will not change the neutural pH of 7.2 to 7.6 that we are trying to maintain.
The amount of “chemical” reduction is in direct proportion to the following items: Amount of ozone gas available (more ozone; more oxidation)
The efficiency of dissolving the ozone into the body of water (only dissolved ozone will be effective; undissolved ozone will off-gas)
The amount of organic load in the water (more organic load; more ozone is needed)
The amount of time the ozone has to contact the organic load (more time; more oxidation)
I do not believe 2 to 3 hours of ozonation is adequate to have a meaningful fenefit.