Kinda looks/sounds like overfeeding to me, causing lockout of one or more nutrients. Especially the part where the bottom half looks fine and the top half gets toasted.
Here's another view of Mulder's chart with a bit more explanation for all the lines:
If one nutrient (say phosphorous) is being locked out/antagonized by another nutrient (say calcium or iron), no amount of increasing that one nutrient is going to help. You have to cut back on the antagonizing nutrient.
I totally agree with
@GenericEnigma that it couldn't hurt to try a different style on a plant or even an entire crop at this point. Personally, I had a lot of trouble with salt based nutes, actually similar symptoms to what you're seeing, and found organic growing with just peat, perlite, worm castings, and dry amendments to be much easier and more forgiving.
Espoma makes great fertilizer blends for growing weed, like Garden-Tone and Tomato-Tone. Just a thought, couldn't hurt to try if you're continuing to have issues with your current method.
Best of luck, hope you're able to find something that works!!