Perhaps 1 page further.
I know the difference between air and oxygen.
That does not make your posts less nonsense.
As I wrote (and read it again) air contains for 21% of oxygen. Always.
So where there is air, there is always 21% of oxygen in a free atmosphere.
Always, except in very exceptionel occasions like in an explosion or in a room with no ventilation, and other enviroments when there is no free flow of air, and where a lot of oxygen is consumed, and on the top of Mount Everest.
I can explain it again, but I guess you are so stubbern that you won't read it anyway.
But then perhaps for other people.
Yes, roots can only absorb DO. But that does not mean you have to give your plants water with a high DO level.
It is much simpeler (and more effective) to make sure that oxygen in gas-form can reach your roots.
This is what most growers do when they grow in soil, in cocos, on rockwool, RFX1, etc.
Nobody in his right mind would give plants in such set ups water with a DO of 9 mg/liter.
You can give them water with no DO at all and still the roots would get oxygen.
Because oxygen in gas-form reaches the roots, the roots are wet, the oxygen dissolves in the water around the roots, the cells absorb this Dissolved Oxygen. Job done.
In Hydro it is no difference.
Yes, you can give them water with a temperature around 20 degrees Celsius with a DO of around 9 mg/liter.
This amount of DO you reach easily with even a small waterflow, some movement, an airstone.
But again, it is much easier and more important to make sure that the roots hang in air now and then, or often. (and yes again: I know air is not equal to oxygen, but it contains 21 % oxygen, always)
This is how all commercial growers do it.
It is not wisdom from a book or some weird websites.
Or blablabla from a company that wants to sell an electrolysis machine.
But every now and then someone who does not grow himself, never has been in a greenhouse, but spends a lot of time on the more obscure corners of the World Wide Web, comes around with semi-scientific nonsense.
Millions of growers around the world (and I don't mean weedgrowers) but farmers who grow flowers, vegetables, fruits are doing it wrong but J. Henry knows how to do it rigth.