Is this a C/M deficiency? I was using 3ml botanicare and increased back to 5ml last feed. only 3 out of 15 plants with only 1-3 fan leaves looking like this. They are located mid way and are all larger, older fan leaves coming from under the branches.
looks like cal def kinda also looks like salt buildup I noticed the leaf margins are curled up which indicates salt build up the leafs are trying to disapate eccess water but can't the other reason leafs curl up is heat stress. the brown edges kinda look like cal def in late stage. the interveinal yellowing could be mag but it usally starts at the back of the leaf not the tips could be nit def but looks more like nute burn due to saltbuild up flush with water 3 times amount of substrate. and the last bit of flush do a very light maybe 1/4 strength but complete nute solution and call me in the morning.lol