They are the same effect. As the shell minerals grow they are dissolving at the same time. Growing and dissolving are two sides of the same reversible chemical

They are the same effect. As the shell minerals grow they are dissolving at the same time. Growing and dissolving are two sides of the same reversible chemical reaction. The equilibrium point is a function of acidity. More acid yields slower growth as well as decreased compound stability. It is not one or the other, it is both.