tips curling and yellow leaves. please help!!!

i've been flowering for 3 weeks now and the tips of the leaves have curled down the bottom fan leaves have been turning yellow and have some holes. i've been using fox farm bg and bb, so I'm guessing it could be a deficiency. please help!!

A pic or two would help us to diagnose the problem. Also hydro/soil, what type of hydro/soil, additives. The more info you give the easier it is for people to help.