Cal-Mag is a myth...
Lol, just kidding sorta
I have yet add cal-mag to my plants. Here is the thing with Calcium intake, a few variables control it.
Ph and
Salt can lock up the plant. Its a defense mechanism to prevent nutrient burn.
Soil Symbiosis is a totally different thing and a major Benny of organic over synthetic. Calcium is prevalent in most soil and even tap water, the trick is getting it to the plant, or usable for the plant. A healthy soil food web will ensure a steady source of calcium by constantly breaking down organic matter. Also
Mycorrhizal Fungi may help bring in more calcium but it has not been proved yet, however it is being
studied.
So basically
if you use salty, synthetic ferts a lot, chances are you
will need to use Cal-Mag, but I feel a shot of Compost Tea will get your food web going and get you that Calcium for a fraction of the cost. To back up my hypothesis, I'll reference nature
Think pepper plants evolved to need cal-mag in nature?
To all you hydro guys and synthetic N-P-K user, don't hate on me.
My hats is off to you for synthesizing nature, because to do it successfully is no easy task.
beneficial bacteria and fungi; they do not
damage living plant tissue and are critical to
making essential minerals available to the
plant. These microbes retain large amounts
of nitrogen, phosphorous, potassium, sulfur,
calcium, iron and many micronutrients in
their bodies, preventing these nutrients from
being leached or removed by water runoff.
The Soil Food Web
Tuning in to the World Beneath Our Feet
by Mary-Howell R. Martens