Hi mate, i believe your PH is to blame. Showing signs of a lockout. Usually magnesium and calcium are the first to show up with a lockout and you can just see the fading which could only be magnesium. Bring your PH down to about 6-6.3 and see if she improves. Maybe do a slurry test of your soil to see where it is at. I hope this helps, good luck and happy growing