^ That doesn't make a lot of sense. I'm not sure how long ago it was that he told you that. Most 2-part additives don't have trace elements in them, and those that do, certainly don't have a lot of trace elements. Nowadays most 2-part or 3-part additives have trace elements sold separately to add as well.
Anyway, the point is that scientifically calcium and alkalinity are taken up by corals and invertebrates at a ratio of 20 ppm of calcium per 1 meq/L (2.8 dKH) alkalinity. Trace elements are also taken up at other relative ratios and may or may not be added to the dosing regime by the manufacturer or the hobbyist. The trouble is that this all looks good on paper, but when it comes to the real world the numbers can be affected by
lots of different things. However, theoretically, the ratio that the calcium depletes will be the same ratio as the trace elements in the calcium mix so if calcium is high then the associated elements
should be high as well, same with the trace elements in the alkalinity mix being low if alkalinity is low assuming that the manufacturer or the hobbyist has added trace elements to the mixes.
For those interested in what
"lots of different things" might be, Randy Holmes-Farley discusses some of the things here: http://www.reefkeeping.com/issues/2004-12/rhf/ Keep in mind it was written 10 years ago, so some of the equipment he discusses is not common anymore.