The colors are just from flushing, with minimal burn to some leaf tips. At this point in the game theres no need to add nutes even if def's are apparent. So close to being finished. FLUSH ON!
I am not sure who Vumar is. With all due respect, he gave you some of the worst advice I have heard. Please do not listen to random strangers online and do whatever they tell you to do. You will learn quickly that this will cost you big time. Instead, consider their ideas, apply it in a logical sense, and trial/error in your own part.
Now, I feed Cal/mag all the way until 3-4 days before harvest. Cal/mag is many things, including cell division. How do you expect bigger buds later in flowering without cell division?