Hook Leaves?

Day 30 into flower and some of my tips are doing this (see pic). Can anybody tell me what to do? It's White Widow almost 5' tall. Thanks in advance.

that looks like the tip is dieing. so what i would do is balance your ph (if your in soil the make it 6.8, and if your hyrdo make is 5.9) dont over compensate with ph up or down to do that either just fill a gallon of water and make that ph 6.8 or 5.9 then just pour it in and youll see some improvements. and dial down the neuts a bit