The solubility of many salts of weak acids (carbonates, phosphates, acetates, sulfides, etc) are dependent on the hydrogen ion concentration. The lower the pH, the higher the solubility because the acid-base equilibrium becomes coupled with the solution process of the electrolyte.

High hydrogen ion concentration drives the formation of the conjugate acid of the anion, which, in turn, reduces the anion concentration in solution. As LeChatelier's principle would predict, this drives the solution process forward. This is why vinegar (acetic acid) can be used to clean calcium carbonate scale from coffee pots.