Your soil frightens me. What, exactly, is that?
It is KILLING your plants!
Unless that is some type of coco I haven't seen yet, in which case you need to get going on calmag plus right away.
If it isn't coco, you are going to have to repot and get as much soil off the roots as possible in the process.
Check the runoff pH. I'm leaning towards pH being WAY out of range causing those lockout symptoms.