Flushed 20 gallons through the growing medium today, in preparation for harvest! I'm 100% sure she was nutrient-locked, PH of the run-off was around 4.5.
From now on, I will pay greater attention to the Run-off PH, when my plants shows symptoms.
Lesson learned! If I corrected her earlier, her potential would have been much greater!
After the flush, the run-off has: ppm is at 80, and PH is 6.