PLANT PROBLEM PLEASE HELP

Im 4 weeks in flower Im using dutch master gold add 2.7 silica plus cal/mag ph 5.8 the affected leaves all come from the upper part of the plant any help would be great.

hydro I take it?

Ive seen this before. Cant remember what it is bit im recaling something with potassium? Or phosphorus, but i thought potasium. Cant remember if its an over or under of it. Ill check back and see if you got an answer so i can see what gets suggested.

Im growing in coco/perlite my run off ph 5.4