Simply called carbon dioxide. It is composed on a chemical level of a one carbon atom and two of oxygen.
It is fundamental for the photosynthesis of our beloved plants. For aquarium with many plants it is really necessary. Obviously at too high levels it turns out to be harmful if we were to have live guests in our tanks. The CO2 concentration for a planted aquarium should never drop below 20ppm (parts per million), use the calculator above to understand your current concentration.
Unlike other calculators, the one used on this site is much more precise and also takes into account a fairly important variable, the temperature
The addition of carbon dioxide in our aquariums allows us to push the growth of plants to very high levels, we must be careful to maintain a good level without exaggerating anyway. It must be said that at 'home' levels it is impossible to reach lethal concentrations for the plants themselves, but if we also have fauna (live guests such as fish or shrimp / caridina / neocaridina) it could be really deadly. So let's use the calculator to understand the right concentration. If we do not have plants, CO2 can be used to acidify the water, i.e. lower its pH.