I use Dyna Gro and have never needed CALMAG . Dyna has a very complete nute spectrum including micro , and Calcium / Magnesium.
I stick religiously to the feed schedule made this line and feed ONCE a Week. The PPM ratio is much less than other nutrient lines and is easy to make the mistake of Overfeeding. LESS IS MORE
Flushing is recommended for this line of nutes. Salt buildup WILL lockout quickly.
I flush at week 4 and at week 6 , I notice that runoff will be quite high if you do not flush your medium. With DYNAGRO , I never had to use boosters , bloomers or additives. I want the strains particular characteristics to come naturally than from extra chemical needs. Molasses may be used as for its simple sugar molecule.
It can burn plants quickly if the strength of your feed is not roped in . 1/4 to 1/2 max. Coco needs you to adopt a DIFFERENT schedule like hydro. Let your plants dilute the heavy nute buildup with a PH water only week.