Your average soil doesn't need that much calcium. Common thing where people are always preaching to dump calmag on the plants because this is what they have "read".
In practice it doesn't work that way. I run coco and barely even add calmag but for once or twice a run here and there. Eventually you will lockout the magnesium and need to add some Espom. Also Calcium is an immobile nutrient so that the plant can only send it to new growth, not older growth. Adding more calmag to fix older growth does nothing.
Also, from my actual experience, some Mephisto strains take too much calcium pretty hard.