Corals aren’t the only animals in our aquariums that need calcium. Snails and clams need it too. Even though the calcium uptake of snails is minuscule, they still need the right water chemistry in order to properly grow their shells. This is especially true for Tridacnid clams, as they suck up calcium like its going out of style. You won’t need a calcium reactor to sustain the appropriate calcium, alkalinity, and magnesium levels for these gastropod invertebrates, but regular water changes or, at the very least, some form of calcium dosing will certainly help.