Why do organisms need trace elements?

This question is relatively easy to answer. Life originates from the sea. This means that the metabolic processes of all organisms, even of those that nowadays live on the ground, have developed in the ocean. Even us humans have inherited in our bodies a small ocean of some kind: the about 4 or 5 litres of blood that circulate in our body, since it is a liquid that in its saline content resembles that of sea water, and in which there are several trace elements in the needed vital concentration. If there is a shortage of a certain trace element, symptoms of illness appear. Something similar happens in our aquarium animals, whose health depends on the provision of trace elements from the sea water around them.


Metabolic processes are nothing more than a biochemical reaction, and in sea water there are dissolved all the mineral substances available on earth, because water permeates the ground, and then takes the substances to the ocean. In this way, in the course of millions of years, were developed all those biochemical processes that corals need to grow and procreate. Therefore, if there is a shortage of mineral substances these processes stop forcedly, creating dysfunctions in the metabolic processes, and the corals get sick. Growth slows down, parasites are able to settle on the tissues, or the coral whitens.

A shortage of trace elements in an aquarium can develop in several ways:

  1. because of natural consumption (animals or plants eating the substances),
  2. because of precipitation (the transformation of substances dissolved in water into insoluble compounds, which are not available for organisms anymore),
  3. because of the exportation of water (filtration on activated carbon, protein skimming, reverse osmosis). It is therefore impossible to neglect to regularly add these substances.
  • Adding trace elements

The easiest way to dose trace elements in an aquarium is to make regular partial changes of water. If the partial changes are made appropriately, you will be correctly managing a nice reef aquarium, inducing a magnificent growth in the hard corals, as demonstrated in the column “Aquarium portraits” by Petra Barg (2004), who does a monthly change of about 40% of water (if you subtract the volume of the ornamental rocks from the content of the aquarium it is almost 50%). Anyway, to quote the old saying, “all roads lead to Rome”, even in reef aquariology. Many aquarists obtain great results by doing moderate partial changes of water (for example 10% every month) and adding trace elements. Especially in aquariums where there are only a few small fish, abundant partial changes of water are not as essential as in densely populated tanks in which big fish with a high metabolism swim, which naturally also produce many nutritious organic substances (nitrate ions, phosphate ions) as waste products. If there is not that much pollution of nitrates and phosphates in your aquarium, instead of abundant changes of water it is possible to do smaller changes (10% per moth), but you will have to regularly add trace elements. This is because it is not necessary to reduce the concentration of these nutrient substances through water substitutions.

To add trace elements it is definitely not necessary to use dosing pumps. They make dosing the trace elements easier and convenient, that is for sure. But adding them manually also works well, as proven by many beautiful aquariums. It is however important to use high quality products, and to not assume that “the more the better,” and use larger quantities than the ones indicated on the maker’s instructions or what the aquarium really needs. We should always remember that these substances in very small quantities are of vital importance (from which the name of “trace elements”), but in high concentration they can be toxic, like copper, nickel, and zinc.