I would either do a water test for mineral content and pH or use ro water/spring water. Just because you us dolomite doesn't mean your pH of you water and soil don't matter, what is your soil pH? too low of a pH will also cause mg lock out, it's not available at those low pH's. P will also cause lack uptake lock out of mg if you have too much, too much sulfur as well. The browning you speak of, it starts as spots correct?
Your best you try, to harm I and I, Aiming to kill.
But I love you still Cause you are here to make prophecy fulfill.