Coco can suck up CaMg and PK can do weird stuff with lockouts; I don't know enough to explain it properly but I've seen it happen. Perhaps this mix just doesn't really do well for this strains needs? I've jacked up CaMg badly personally making Coco based soils for the veggie garden. Lots of time cooking and P heavy teas are my fixes for this, and for some reason going to 2"+ of hardwood mulch versus a light coating. That seemed to stabilize some imbalances, I just choked the smart pots to the brim keeping air space for the stem and things got better within a week or two. Correlation doesn't mean causation, but...
When I'm doing a chem only grow I use clay pellets thoroughly washed and soaked in pHed water as mulch, same thing, as much as the container allows. Seems to have a similar effect. I think this is due to less surface evaporation, dry out, and salt concentration at the top of the root zone. More uniform conditions for nutrient exchange. You even get some root growth into the rocks when you do this with tomatoes indoors.
When I'm doing a chem only grow I use clay pellets thoroughly washed and soaked in pHed water as mulch, same thing, as much as the container allows. Seems to have a similar effect. I think this is due to less surface evaporation, dry out, and salt concentration at the top of the root zone. More uniform conditions for nutrient exchange. You even get some root growth into the rocks when you do this with tomatoes indoors.
