super sour diesel

Hi Really confused !!! The plant was doing great yesterday,today notice these leafs , My last foliar feeding was 2 days ago!? Mybe it cause this !!! I’m just 2 days in flowering . Also add 4 ml cal/mg today . What do you think?any defi? Also lowering ppm by 300,ph is 5.8 . Dwc system Any idea?!