duck,
You are probably on to something. With lots of water "flow-through", oxygenation may not be necessary, as it is for an aquarium, for example. I am now more concerned about salts buildup in the Combo Mix over time, so that is why in the Guide, I am recommending periodic use of Clearex to "flush" the Combo Mix.
My concept with the ozone generator was that it *might* accelerate root development with the injection of more oxygen. Another Myth-Busters Challenge for next Season!
Raybo