Questions tied to the CANNA product line rather than to nutrition in general: Terra, Coco and Aqua, the additives that sit on top of them, and how the published feed charts behave in water that is harder or softer than the one they assume.
CANNA formulates a separate base line for each substrate instead of one bottle with a substrate-dependent dose, so the same brand name covers different chemistry in peat, in coco coir and in a recirculating system. Coco and Aqua ship as an A and a B bottle because calcium salts and sulphate salts cannot sit together in a concentrate without precipitating out; poured undiluted into the same jug they form gypsum and the plant receives neither.
Two things are worth settling before a thread turns into an argument. A feed chart is written against an assumed water source and an assumed substrate, so following it exactly can still overfeed in tap water that already carries calcium and magnesium: post your source water reading with the question. And Rhizotonic, Cannazym and the Boost products are additives on top of a complete base, not a base themselves.
Where to start