Something is a little out of balance in your mix, because it is healthy otherwise.
K-def, S-tox, P-tox... if you can calculate the PPMs of what you've fed your plant over time, you could deduce what it is fairly easily. check out my nutrient spreadsheet or google for a nutrient calculator to convert your labels to PPM and add it all up.
k - <210ish ppm and even that can cause some plants issues.
p - <60ppm
S - <110ish
Generalizations... ballpark firgures of upper range
A lot of this depends on the ratios of nutrients as well as the pH. A significant shift in either can drastically change what "optimal" is.