Brown Tips

Help! I have a flood and drain hydroponics system. My babies are in there veg cycle and they have brown tips on all the leaves except for the brand new ones on top. I'm using FoxFarm. Keepin ph at about 6.0.
Thanks

Looks like nutrient burn to me. Maybe flush it?

Thanks i am going to flush today

Over nuting.

Dito, over nuting...What is your PPM? flush and kick it down alittle...It will look worse later, but fix the problem now and the next set of leafs will not suffer as much..