Agreed, trace elements are the stuff that occurs in minute quantities, and would require sophisticated lab to measure. A lot of the stuff sold as additives,other than calcium and magnesium supplements are for the most part not needed if one does reasonable water changes. Also using 2 part calc/alk additives or a
calcium reactor with help keep the needed ones up.
Personally buying and adding special trace element supplements and exotic secret formulas is a waste of time. Most of this stuff is high profit making for whomever is sellling it, and can do more harm than good if one applies the "a little is good, alot must be better" sort of logic,JMO,FWIW
