they look fine bro.
the dying leaves (turning yellow/brown) looks like the old growth and the plant overall is looking amazing.
your still feeding at 1/4 strength? if your contemplating on feeding TB and start bloom you certainly can.
plant just looks hungry for some N -- i would personally feed @ 1/4-1/2 strengthCHART week 7/8 schedule (thats all 3 GB/TB/BB) see how they react.
follow up with week 5 (TB/BB only during flowering) for the next feed or choose a water only
Even the white hairs are starting to get brown should this be happening