Hi mate, as Uk420show says it looks like a calmag defiency but it would be worth checking your root zone and making sure your ph is on point. If it ever wasn't, you may be experiencing a lockout. Your EC is 1500 so you shouldn't really be seeing much deficiency. I would get some humic acids and beneficial bacteria in there to help her recover... Maybe even some gypsum to give her a boost and balance out ph. I hope this helps, good luck and happy growing