Look guys what picture i did saw today on another forum grower's discussion. Now i do see when and what defficiency is mostly possible to happen, i have seen these things for many times in my grows and this picture explains these very well! Maybe it will be useful to you too.
BTW here goes my friend's plant - also RC, grown with strict defol and stuff, Canna / soil, tomorrow it will be harvested, waiting to get my hands to some of these candies