Two Little Fishies C-Balance 16 oz., two bottle packages. Each set contains two 16 oz. bottles, for a total set volume of 32 oz.C BalanceTwo Part Balanced Ionic Supplement of Calcium and Buffer for Marine AquariumsThis two part calcium and alkalinity maintenance system adjusts calcium, magnesium, and strontium ions to Natural Seawater ratios, and achieves a balanced ionic residual. Makes replenishment of calcium and alkalinity easy, and keeps your calcium and alkalinity in perfect harmony, assuring the optimum conditions for growing stony corals and coralline algae. Rapidly raises calcium and alkalinity without disturbing ionic balance of seawater. Easy to use no dosing system required. Replenishes salts lost to protein skimming. Promotes vigorous growth in coralline algae and stony corals.