Hi, I am a first time medical grower and have run into problems. My temps range from 76-84 in the day and to low seventies at night. The leaves on my plants are turning yellow could this be nute burn? I added some revive from advanced nut. to them yesterday because they were yellowing but the yellowing has progressed I watered them also. Do they looked under watered still? I have no idea what wrong please help here are pics.