One of my plants just died over night 1 week into flowering (white widow). Looks like another one is dieing now too. This is some BS any advice will help. i started useing open sesame the last couple waterings and they were looking good at first but they pretty much went to shit now. I killed the one that died first in the first picture and the second one that looks horrible is the second picture. The rest are still looking okay.
Hard to tell. But you may have locked the plant out from overfeeding. How much of the new stuff did you provide the plant? Do you measure PPM or do you feed by gallon ratio? I'd be curious to know how much you were feeding with the new stuff AND what your soil medium is. I would pull the plant out of the pots and look at the roots quick in a dimly lit environment with very clean hands. I like to gently rough up the roots with my fingers, especially if the roots are root bound (spiraled around the pot on top of each other) and then put some new fresh soil in the pot and rub some on the roots. Water the plant in with fresh clean (non tap water or tap water that has sat out for 24 hours. Run a few gallons of fresh water through each plant that is showing issues and then it dry out before watering again. Have you checked the runoff for pH issues? Those are my suggestions.