Abstract: A salt-composition for stabilizing the carbonate balance in the aquaristic area (i.e., aquariums), wherein the salt-composition has major components of at least 10 weight percent formates. The salts contain no fatties, proteins or sugars and stabilize the carbonate balance individually, being essentially disconnected from biochemical metabolism-cycles. The alkaline, ready to use solution of the salt composition supports advantageously skeleton- and reef-building sea-water-systems in their bio-mineralization. Use of the salt-composition to acidicly activate carbonate-containing aquaristic ornamental stones provides special substrates, on which bio-mineralizing systems of sea-water aquariums settle and grow quicker and better.