looks like a lockout due to PH problem/fluctuations.
what are your temps/humidity like?
what is the ppm of your plain tap water?
If your tap water is over 200 ppm Magnesium will be locked out due to the calcium in the water. Magnesium can get locked out by too much Calcium (Ca), Chlorine (Cl) or Ammonium Nitrogen (NH4+).
Try filing out a
Nursery Questionnaire for better diagnosis.