i'm not sure man, but i can make some general suggestions...
make sure you completely change out ur rez/nute solution at the first sign of any problem. then bring it back up to the desired ppm with fresh nutes at the prescribed rates (but not necessarily at the proscribed quantities). plants can pull a particular micro or macro nute faster than the rest and then be deficient in that alone though the ppm's have hardly moved.
also, anytime leaves are healthy green enough (not pale) and they start to kink or curl or bend or twist then start looking at either over-fertilization or pH problems or nute lock out caused by poor water quality.
ya, that's reeaaaal helpful, right ?!
basically, make sure you are using RO water alone... then mix fresh as proscribed. make sure your pH is between 5.5 and 6.5 (might as well shoot for 6.0) ... and then make sure the ppm's aren't too high. personally i don't usually push them past 800 ppm, especially when having any signs of trouble.
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