Zinc or light burn ? Help

week 6 in flower white widow. 2 - sf2000
Big bloom and mega crop food.
The tips are browning and yellow . Any help is appreciated . Lights are 16/18" ofd top.

Personally I think they look good man. Could be slight nute burn. But your in week 6 already. How much are you feeding ( ppm )?

Not real sure on the ppm this is my first grow. I have been feeding about half a gallon every 2 to 3 days . When the soil gets dry . Just the same as in veg. Should I feed different in flower ?