i dont think you cant have too much light as a weed plant. think about this, how much lumens is there on a bright sunny summer day? theres at least 10,000 lumens. normally indoors, even with HPS, plants get only 2500-6000 lumens.
doesnt mean that your pH doesnt get out of range, it is accurate. you can get consistent readings, but the wrong readings if not calibrated.
please dont ever cut the roots off a plant because its too long. what if i cut a portion of your small intestines out instead?
i dont think having direct PC fans on the rootzone is good for the plant. they need some O2, but not that much moving air. it gets them dried out easier. as far as i am concerned, they need dissolved oxygen, not air in the rootzone
i dont see why you need to flush with h202 unless theres a oxygen problem, or you got some disease/pest problem. normally, i would not add H2o2 to my weed because it kills the beneficial microbes that helps it uptake nutrients