: The edges of the leaves may become yellow or bright green and may start feeling crispy to the touch. The light green or yellow coloring may also effect the veins of the leaves.
It is very important to maintain a proper pH in order to avoid a magnesium deficiency. Adding more magnesium to a system when there is a pH lock-out will only make the situation worse because the plant will not be able to absorb any magnesium until the pH has been corrected. Flush the system with properly pH'ed water that contains a full set of proper nutrients and see if the new growth starts looking healthier.