Blue Dream'Matic FastBuds

The upper leaves show worse symptoms now. The leaves are getting more yellow and brown. I am not sure why, maybe because they started flowering early and are thus finished early, or there is a deficiency of something... For now I will give them only ph corrected water without nutrients, and in the mean time I am searching for an explanation. Day 54: The problem has been identified! It was light stress that had been developing over a longer period. All the leaves exposed to direct light show very bad symptoms. The leaves that where not directly exposed seem perfectly healthy. I am now using less light, and let's see what they think about that! I also continue with feeding again with an EC of 1,3