Carencia

If you mean 1400 ppms based on the 700 scale, then that's an EC of about 2.0. That's about as strong as nutrients should ever get and this late into flower, they probably don't need that much. Try watering with pH'd water alone for a few feeds and see if she recovers. It's not a great picture colorwise but it looks like your soil may be too hot from picking up residual nutes. If your runoff is higher than your feed, you are feeding too much. If you're in hydro, then test the reservoir and see if it increases day to day. Also if in hydro, your pH is a little high, for soil it's perfect.