My plant in my PC Case grow is about the same size and starting to show the same effects this evening. I am feeding at an EC of 0.7 DWC. First time using DWC but when using coco I would slowly ramp up to 550ppm/1.1EC for veg until flower. I am going to be increasing my ppm levels as I am in the same boat as you, ,I really don't think there are any pH issues. Water temps in check?
Cheers,