Been having a heck of a time with this problem. I've done as much research as I can via internet. And cannot identify the problem. I think it may be calcium deficiency but unsure some advice from true experience would be very welcome thank you.
Crap pics could be calcium, are the leaves toward the bottom? Could be lack of light or nitrogen but would be easier to tell those deficiencies apart with better pics .
Looks like coco husk, you should never let coco dry out. When coco dries out it locks the old dried nutrients to the fires and prevents new fertilizer from attaching to it for the plant to use and causes nutrient lockouts that show up on the leaves. I water my coco when ever the pots feel lighter in weight but are still moist.