Yellow crunchy leaves

it might be something you want to reduce a bit though. your sugar leaves in the buds should not yellow like that. Fan leaves degrade.. sugar leaves may have a tip degredation, but should be fairly healthy until harvested. I can't tell color very well in pics.. are the leaves glossy or extra dark? if yes, more likely a toxicity. adding pk is fine.. know your ppms of what you feed and you can avoid such things with minimal trial and error as opposed to blindly doing it and coming to the same conclusions, hopefully, in a much longer time period by comparison. it's not just.. toss this in and it works.. this is chemistry. it's complicated. ratios and concentrations are equally important, and many of the elements have the same bonding sites (hence ratios are important). fertilizer is one of the smallest components of growth.. minimal in comparison to light and CO2 from transpiration. you can't force it to do more than its genetics allow.. you can only give it what it takes and accepts in a healthy and optimal way.