Nut burn, dial back for a second.. if you have an EC mater than can help, but don't expect the reading to be accurate in any way. (similar to why lux doesn't tell you anything about PAR on its own.. it's a poor measuring stick for measuring amount of dissolved solutes, even so, if it is extremely high or low it is a good indicator.)
get pH in order, get TDS in line.. should improve quickly.. .don't let it progress... I have the same thing with some vege crop - ggxww you can see it in my diary. I overfed.. need to give pH-only for a bit.