The trick with coco is it needs to be prebufferd with cal mag before use.
Simply put coco is like sponge to cal mag and pre buffering fills these holes
Even if it says it's bufferd do it anyway.
Always water to ample runoff.
With the Canna line you should use Canna Coco A B
Just ordered the BCB 680 I plan to separate into a L shape to grow in the corner of my space
Figure it will be a lot easier to tend my plants in a 6x6 area.
I'm stoked