it sounds like it may be high heat and humidity and a lack of fresh air,if you have an outtake fan in your cabinet,let it run continuously,give them the full recomended dose of nutrients,and check the ph,then wait a couple of day to see if that helps,if you dont have an outtake,place a fan above the light fixture as well as below(on the plants) to promote air exchange and remove the extra heat and humidity....bonbon