it looks like its could be alittle bit of both, maybe becuase of the mg def they burned alittle more, showing up on the top leaves. It looks like you might have the ph wrong also, i know it the waterfarm its hard to balance it for each unit. With the worng ph u will lock out nute and at the same time if ur at the max closeness with the light, u could potentially burn them if there not getting all they need. your leaves are also very dark in color tward the tips indicating another deficiency.