did you say 2 feeds, and one water...@ 2EC? that is good for a full mature plant in full bloom at peak growth...even for me thats high...i got max at 1.4-1.7 EC, and i feed water feed water....
you must remember, the more intense the light, the more water and less nutes the plants will want to drink, so over time the nutes will concentrate themselves because the plants will be drinking more water and the salts will continuously build up, until the plant can no longer transpire correctly...
not saying htis is for sure your problem, but it is what i am thinking at this point...
how old are your plants? or how tall?
a buddy of mine just had some issues with his plants, he never had these issues before, so i asked him how his plants looked, imediately o tild him over fert, he said thats impossible....i then asked him how he feeds, he said 1000 ppm every watering, lol i asked him why? he said because our mutual friend trold him i fertilize every watering lol...i laughed because when i do fertilize every watering, i fertilize @ max 650ppm, and make sure to have 20% runoff each time i water, he was ferting at 1000ppm every watering with no runoff.....
thats another thing, runoff, you need to have between 10-20% runoff everytime, of not, you will have salt build up, if you want to have less runoff, you need to cut your nutes by 1/3 to 1/2