It looks to me that you got bit toxicity going on. You getting some clawing going on there . It's only good to get worse if you don't lay off the nutes a bit .
Don't even know his medium , think its soil . I would just be running clean water through them for couple weeks , wash the nutes out over that period of time . At the same time they using up the feed ,
Just give it or them? Plain ph'd water from now till harvest , no point flushing to rid toxicity now , your plants are almost done so by the time they finnished you will of got rid of the build up and have nice clean buds