Brown and Curling help me please

I have 4 NYCD and 2 Violator Kush going right now and the Kush are not doing well. They are covered in trichs and seem like an amazing plant but I cant fix the problems I've been having for the life of me! The leaves at the top of the plant are dying on me. It began with some rust colored spots that slowly took over entire leaves. Now the rust color is getting darker as the problem gets worse and is effecting all bud sites/leaves. The branches are weak and cant support themsleves even at 30 days flower, even at smaller budsites. They are just flopping over and even upsidedown without righting themselves. I thought it was a calmag problem so I added calmag to my water (tap). This wasnt helping so I folar fed, still to no avail. The soil is at 6.8-7.0 FFOF with 30% perilite. I am using the fox farm trio of nutes at the recommended strength. I have tried flushing the plant with plain water, backing down on nutes, adding extra nutes, cal/mag, and nothing is helping. This is my favorite plant but it is just ooking like crap now. The leaves are curling upwards, turning brown, and hard. I dont know what to do from here??? Anyone have any input. Ph is always adjusted when feeding to 6.3-6.8 I have also given all my treatments some time. This has been an ongoing issue since the 2nd week of flower, I am now at day 40 of flower.

2 more pics. lights are 24" from the tops, temps are between 77-82 lights on and 68-72 off.

What you have described, sounds like either Potassium or Manganese deficiency.
It is absolutely impossible to tell anything from your pictures, when taking pics to aid in diagnosis of issues it really is best to take them just before your HPS lights come on or just after they go out, just turn on a normal light long enough to take your pics.

I'll try to take some better pics. thanks for the input. brb

The single leaf is newer growth (first signs of deficiency). All are taken in normal light.

I just dont get how I can be so deficient. Ive fed them, flushed them, ph adjusted to no avail

About the branches bending over, VK flowers get pretty heavy. I had to prop up my plants.