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.