Try dropping your nutrient strength a little more Ca/Mg deficientcy can usually be solved by using tap water and allow the Ph to drift between 5.5-6.5. Roots look healthy though.
There have certainly been advancements in 'organic hydroponics' in the end the plants are still recieving the same basic minerals they get from a refined mineral nutrient. The whole point of water culture is to maximize uptake of nutrients, water, and oxygen to the root zone. With organics you have to depend on microorganisms to break down complex organic compounds into refined minerals the plants can use. I've also seen plenty of funky smells, clogged drip rings, slime, ect. If you are heart set on using Organics with water culture go for it. I prefer easilly dissolvable mineral nutrients that are clean and easy to flush from the medium/system. My goal when growing cannabis is to maximize potency and flavor. I prefer pot that tastes like pot so I don't use any sweeteners or flavor additives, just give it a nice flush and let it ripen nicely. This results in a very pure product, it does not taste like soil or additives, it does not crackle a pop just burns slow and even. The taste and smell tends to be specific to the strain (IE Skunk smells and tastes like skunk). Some people like the 'complex' taste of organic bud I prefer a cleaner taste and that is the main reason I grow hydroponically.
Looks great! Glad to see they are recovering well. You should not need to flush during veg with DWC just change out your nutrient solution every 2 weeks and top it off with fresh water in between change outs.
I would not use Voodoo juice and H2O2 together. Hydrogen peroxide does not kill selectively so it will kill all the beneficials you are adding. Changing your Rez out often is also a great preventative, which you are already doing
