The reason I mentioned concentration is that many people want ozone units for multiple purposes. And if they do want it for other purposes they are not apt to say so for obvious reasons.
And there are other factors also affecting the ozonation of water, such as bubble size. Smaller bubble size equals greater surface area and faster saturation. There is also a factor of saturation to begin with. Spring water is more saturated than distilled water for example.
And from all my research I have never seen where the cold corona systems using the double dielectric I mentioned generates acids with an air feed.