sorry I meant to type "sulfer" instead of "Nitrogen"..lol
MOLYBDENUM (Mb) seems to be your problem.
it promotes a shortage in nitrogen so some of you are right but its not exactly a (N) deficiency
if your problem gets worse this can cause a copper and iron deficiency.
maybe you should try lowering the PH to 6.5 to get more iron out of ur nutes
i will try to find more info for you guys
i'm feeding 1/2 strenght once a week with a little e-salts...should i go full strenght? or 6/5?
Or simply switch nutrient brand?