You seem to love your plants and seem to be doing much of the right things. Other than testing ph/acids I try the keep it simple cause im stupid method. Check some things out... does too much magnesium, calcium and other minerals have neg effects, answer yuuup. Hows your soil with other nutrients? What if any of these nutrients are in the clay you use? Are you watering with well water? whats in that? try distilled water through your next 4 feeding cycles and see whats up, should be feeding every other water. various water sources have clorines and metals that are not good for plants, its ok to germinate with but that's about it. some strains are prone to various colorations and by the pics im not seein abnormal colorations. actually had leaves die? Color on your plants are lookin tasty hang in there...