Some of the fan leaves are changing colors and looking like nut burn but most of the plant looks as though nothings wrong with it. Any help?
just looks like beginning of nitrogen deficiency, if you are feeding regularly with min 1.2Ec nutes, it maybe due to a low ph. locking out N or S.
I grow by the philosophy of "Old Leaves are Old News". If your new growth is good then not much to worry about. However after looking at your photos, I agree with JoeBlow81. It looks like a N deficiency to me, and if you are regularly feeding, then you need to check the pH to insure you don't have a lockout going on.