Black splotches on plant. Yellowing leaves

Hi
Soil 75% coco 25%
30 gal beds
Temp is 91
Hum 74
Week 4 of flower.
utilizing only teas.
Plants have been and nice green up until a week ago. All of a sudden they developed small and large black blotches and leaves are turning yellow. The whole plant looks yellow. Edges are curling turning black and dying.
I thought it was potassium or manganese deficiency.
What are your thought and also how do I fix it ?
First pic is the top of canopy

Too hot

SBNDB said:

Too hot

Click to expand...

Damn. How much do I need to get it down ? Also how did you know that?

10 degrees would be nice assuming you have LED lights 78-82ish degrees is what you want. Idk how i know it lol. I’m not saying thats your only problem maybe you have others but i think you gotta start there.

Too hot of temps and only tea might be underfeeding them nutrients esp with a coco based substrate.