Hello Illusion. Nice N Bushy! I would try half grow and half bud nutes at this point. That should take care of any excess N problem. I don't understand how you can be getting burns at PPMs under 500 when you're in flowering. Usually I try to take mine to 1700 or 1800 in the middle of flowering.

Did you know the first 2 sets of photos in your grow won't expand?