Abstract: The invention concerns a method for continuous long term dosing of CO2 in biologically used media, comprising the steps below: i) expelling an aqueous acid solution from a storage container by means of a chemical reaction which generates gas pressure, ii) dripping the acid solution into a solid and/or liquid carbonate or hydrogen carbonate composition, and iii) supply of the corresponding CO2 to the medium which is used biologically, as well as a set and a reequipment set for carrying out this method.