If you'd really like a diagnosis that counts...fill-out the damn troubleshooting form. (as mentioned a few days ago) This game of back-n-forth is doing nothing to help your plants.

Looks like ph lockout and overfertilizing. But without the info you would provide in the troubleshooting form, (the link is in my signature) all previous guesses are...guesses. No, it's not heat stress.

I'd ditch the Superthrive if using a 3-part nutrient system. The stuff is crap anyway. And these days...it's real expensive crap. Superthrive Myths

I'd also stop spraying the already stressed plant with a product from the world's most expensive additive company until you get them back on track.
Rusty Trichome Reviewed by Rusty Trichome on . I need help urgently..my plant is dieing After a month and half of taking good care of this plant here come the problem. as you can see the brown spot is all over the leaves...starting from picture 1 brown spot start showing mainly from inside out picture 2 starting showing some yellow spot within the brown spot then picture 3 the leaves starting to die out. the picture 4&5 is taken from the tree...this symtom is spreading all over the tree and its killing my tree..one of the plant is turning all yellowish...I need help urgently to Rating: 5