When I woke up, one of the plants has a tip of a leaf that is dry and burnt. I'm using a 300w LED. Two other plants only have slightly yellow tips on the upper leaves, just small tips. Too many nutrients?
Looks to me like a Potassium deficiency on that leaf(if near bottom of plant). Where on the plant are those pictures? yellow/brown tips can be either nutrients or light burn. Light burn usually has twisted leaves.