Let’s play name that deficiency!. Pale spots on sugar leaves, Bud rot??.

[PLantAsEED]

I have 3 plants, all humboldt dream but one is giving me odd deficiency or disease that I cannot pinpoint. Maybe those more experienced can explain what is happening and how I can fix it before the crop is ruined.

planted in 3gal pots, 70/30 mix of coco/perlite, day 44F, using AN sensi bloom for coco & AN big bud for coco. Run off is 5.7ph and 1250ppm (my water is 300ppm).

The issue started a few weeks ago with one cola and now effects maybe four of them on the same plant. Started with spotty sugar leaves that progressed.

Need guidance

 

[Habosabin]

Light stress? Could be lockout. I had similar on my auto grow. Shouldn't soil runoff be in the mid 6s? Calcium doesn't uptake until 6.2 from my understanding.

What's the ppm going in?

If stems are purple could be phosphorous.