Remineralizing filters are used to add back healthy minerals, such as calcium and magnesium, to water that has already been purified - usually through reverse osmosis or distillation. These purification methods are so thorough, that they can leave the water with close to zero mineral content - making it taste ‘flat’ and with a slightly acidic pH. The calcium and magnesium added back to the water with a remineralizing filter give the water a much more natural taste, and will cause the pH to adjust back above neutral to an alkaline state that many Aquatell customers desire.