Plant looks like its dying

Hi guys thanks for the input there not ready yet so I know the yellow is a problem but I think you have solved it I am gathering it will be salt build up and can't be Heat stress I have a monster at the side of these and that's fine if anything the other 3 not getting enuff but I upgraded to ts3000 so should be good for light now. Is it not to far gone for flushing and feeding again?

Stop all the nutrients for a flush—- and maybe get off the auto pot if you can. Get that ph back to normal—- problem with all visual deficiency is that you see everything 2 weeks later. I think is just ph—- get back and then back on the nutes. Good luck ✌️🏻💚🌿

Sounds like salt build up, flush your medium and put a fresh batch of nutrients. Excess nutrients can block other nutrients from being absorbed. Your pH should climb or stay the same. If your pH drops and keeps dropping then there's probably to much nutrients for the plant. Also that could be light stress, or heat stress as it's mainly the top of the plant. On another note, how far along in flowering are you? If your near finish then yellowing or loss of color is normal.