When working with LED panels, the feeding is much more demanding, as it stimulates 100% with the colors given by the LED... I recommend increasing the feeding and trying with a bit more EC for the next watering, or administering about 700cc of water with fertilizers for 2 days (or dividing a full dose of water over approximately 2 days)... I mean, if you administer 2 liters of watering per plant, divide it into 2 or 3 days of watering! Cheers!