the purpose of this invention is to provide compositions useful for promoting the growth of calcareous organisms present in a closed system aquatic habitat . particularly , to composition capable of efficiently delivering calcium and carbonate to the calcareous organisms . most particularly , to a composition effective for enhanced delivery of aragonite to a closed system aquatic habitat where it dissociates into bioavailable supplements , such as , calcium , strontium , magnesium , and carbonate ions , whereby enhanced growth of the calcareous organisms is achieved .