One of my ScrOG plants is DYING

If possible, I just want a quick diagnosis.

ScrOG, flowering day 43.

Three plants. Left, Bio-Bloom (50ml/10L). Middle, Lucas 5:15 (15ml + 45ml/10L).



Right, Bio-Bloom (50ml/10L).



My temps were high before (36-38C), but have been 28-31C for the past week, which was BEFORE this issue occurred.

So, that rules out nutes (as the Right plant is receiving the exact same nutes), and heat.

What else could it be?

The leaves are basically dead, what could this be?!

what is your PH and PPM? is it soil or hydro?

Soil, ph 6.4-6-9, 700PPM.

that seems like normal numbers... not sure... maybe a p or k deficiency? how often do you fed them? maybe a salt build up?

Every two days. No, I flushed. Still wouldn't explain how it's only one plant.