I think what he meant was that Lucas has plenty of MAG and that the true effect of cal-mag in this situation is that it is supplying the much needed Nitrogen (2-0-0) so the recommendation is to just increase your GH micro a bit. It is 5-0-1. Loaded with N and Cal. Is that right?
Correct.
. Nitrogen is not the enemy, contrary to the paradigm.
Mg is essential because it is required for Nitrogen uptake. Mg def plants display slight N def (yellowing at margins) even though the N is available because the plant cant process it without Mg.
That said, many times over I see people adding Mg when all they really need is a N boost. In my experience, N def is much more common than Mg def. Like I mentioned above the plant reacts in the same way to both deficiencies so determining which one it is can be a challenge. The advantage cal-mag has is it gives both. The PBP line rubs me wrong though because the base line has NO mg in it forcing you to purchase their additive. Grr.
You can mix a great soup with most any 3-part nute. No additives needed. GH, AN, whatever. You just have to toss the "feeding schedule" out the damn window and feed a 3-1-2 blend in veg and a 1-3-2 blend in bloom after stretch. I use a 1/2 bloom, 1/2 veg mix for wks 2-3 of bloom but that's just because I happen to dump on that schedule and it is an easy blend. If you are looking for an easy 1-part mix, dynagro rocks.