Nute burn is a definite possibility, as Knowm mentioned.

Also, browning, crispy tips can be the onset of potassium deficiency. This is not to say that the ferts do not contain enough potassium. One thing to watch out for sometimes is to provide equal amounts of Phosphorous (P) and Potassium (K). Excess P can lock out access to K. Sometimes switching to nutrients with equal portions of P and K can balance things out (your MG ferts had twice the amount of P for K)

No worries about the amber hairs at the bottom. they're just the older flowers, I imagine.

good luck!:thumbsup: