ChemistryPackage now has a sophisticated approach to handle complex equilibria problems. Imagine that you want to know what is going to happen to an aqueous sample to which you add calcium hydroxide, but where you are taking into account dissolved carbon dioxide and the potential precipitation of calcium carbonate. This system involves seven simultaneous equilibra and involves four phases (aqueous solution, gas, and two solid phases). ChemistryPackage can solve this problem for you in chemistry-standard notation. This example is worked through in detail on the complex equilibria explanatory page.