Auto Blue Dream (First Grow)

Watered with nutrients at the beginning of the week. Since then flushing with ph balanced water and noticed that runoff is 5.3-5.5 PH. I wasn't watering with the runoff for the whole period of the growth which led to the bottom of the medium filled with salts. Now I'm flushing with 6-6.3 PH every other day and aiming for 5.5-5.7 ph of the runoff. I was scared that the tips of the flowers are burned because the lights are too close, but now I see that flowers just have like dark purple colored tips. Also, leaves around flowers begin to become dark purple. γ - becomes really big, probably gonna have the highest yields. Lower buds not getting enough light, I wasn't sure to prune or not to prune at the begging of the flowering because of my lack of experience, and now I don't want to prune cause I don't want plants to get stunned. Next grow I will prune all of the lower branches.