ca and mg are two different things, and i don't think that looks like eithe rone.
both will have spots of some sort. Mg wil also have interveinal chlorosis. P and K tox can cause Ca/Mg deficiencesi.. it's complicated... lol.
you need to know whats in your fertilizer.. if it has 100+ elemetnal ppm of Ca, you don't need to add Ca. it exists in abundance and if ther eis a problem showing that, it's because of pH or lockout -- a far more common issue.
unless they leave it out, and if they do it's to make you buy more stuff beacues it is an essential element, you may need some... but, also you need to find a different brand, if that is the case.
google how to convert plant labels to ppm and go from there.. read your labels, make a spreadhseet.. know what you are giving you rplant or guessing about it will only cuase an infiinite and unending cavalcade of problems.