My autoflower is in coco. I've been nute feeding at 500ppm and also foliar spraying a calmag 500ppm solution at nights off. It seems to be a calcium def from what I see on PWE.
I plan on flushing tomorrow at 6.0ph with florakleen and then feed next day at 550ppm.
Open
Leaves. Color - Dark-brown
Leaves. Color - Black or grey