indeed. the dark leaves are fucked up from excess salts... luckily the new growth is ok. the plant shows signs of P-def. It may been locked out.... but the plant looks sort of light hungry... or is this a strain that is known for long internodial length & thin stems + this typical tendency to purple their stems... Do you use Mycorrhiza?Slow down on nutes, your good.if you have super dark leaves and brown spots, likely over nuted, not deficiency. New leaves look healthy.