I'd like to add that the first picture of K deficiency - to me - actually seems like a case of over-watering. Over watering causes symptoms similar to P or K deficiency, and that soil seems drenched to be honest. I've seen this over a hundred times back in the days, and I still do every now and then on some fora. I didn't read all the pages here, maybe someone mentioned it before me. If so; excuse me!