Yeah my friend this is classic overfeeding, when your plant suffers from overfeeding it is essential you remove the excess nutrients in the medium and in the roots. To do this, you need to flush with pH water (5.8-6.3 for soil) If you want to make sure you're doing it properly, you can measure the PPM of the run-off, this way you'll know when you have washed off the nutrient excess. Hopefully, I answered your question and remember Happy Growing and Free your mind one puff at a time.