HELP!! Overwatered or Heat stress?

This is my first grow and post. This plant keeps giving me problems but I can't seem to figure out what is wrong with her. I moved her closer to my HPS 400W around 12 inches and then the problem started but I also gave her a good watering around the same time. She is in a 3gal bag with organic soil. PH is around 7.5 She gets very little nutes because she burns to easy. she is in her 3rd week of flowering. any advice is helpful.

i would say just flush it good and wait till the top 3 inch's of soil is dry to water keep that air moving around you will be fine

this is getting worse everyday. Now the fan leaves are getting dark brown spots all over the leaves. HELP MY PLANT IS DYING AND I DO NOT KNOW WHAT TO DO!!!!!!

overwartered...... heat stress causes yellowing around the edges on the top layer of leafs

now that i looked at the last pics it might be both... that sucks