I have looked through your photo gallery. Yes your plant does have some nutrient burn. The nutrient burn on your leaves will not heal but the plant should be alright. I would slightly reduce the amount of nutrients you are feeding.
Before I started growing, they all looked the same .. even Indica/Sativa. Now I see different shades of green, a certain vibrancy or not, and all sorts of other little hints that tell about the plant's condition .. offcourse I dont speak 'plant' fluently , and my translation is sometimes horrible, but she's forgiving
I would not be too concerned if only a few leaves at the bottom of your plants begin to yellow. When a lower leaf yellows it is either due to low light or the plant using the leaves as stored nutrients.