BlackJack needs your help

Ive gota problem starting to show in both my AK48 and my Black Jack they are about a month old and went into flower yesterday. Saw a few light color spots on the lower fan leaves yesterday when i watered and i hit them with 1/2 strength grow and 1/2 strength bloom 2 part nutes. Also a dose of calmag. I am using water ph'd to 6.0-6.5 . being grown in Roots Organic soil. All i know to do is flush them but i would really like to figure out what is causing this.
This morning the leaves are brittle and will break off in my hands.
Seems like everygrow has something new happen.

no advice?

Well today it appears to be a little worse. I guess i will be flushing with phd water. Anyone have any ideas what is causing this?? it almost seems like the top skin of the plant is peeling off on the light colored spots.