Take everything you see on You Tube with a grain of salt--anyone can put anything up...it doesn't have to be true. However, he did state that he used it because he had a root problem--the reason for the usage was a problem, the small amount of extra O just a side benefit.
I have grown DWC for about 10 years. I would not add H2O2 unless I needed to. A good air pump and a stone or 2 will provide all the O you really need.
I mentioned pH'ing after adding nutes because in one of your above posts you said that you pH'd the water and then added Cal-Mag.
