Seachem Replenish is a proprietary blend of salts designed to replenish physiologically relevant minerals that are removed by reverse osmosis or deionizing filtration. Replenish restores General Hardness (GH) using a balanced blend of both “soft” (sodium, potassium) and “hard” (calcium, magnesium) salts. Restoration of mineral content is essential since a complete lack of minerals will result in osmotic stress in those species whose osmoregulation systems are adapted to a mineralized environment. Severe osmotic stress can result in osmotic shock, which will lead to rapid death. To restore GH in the planted aquarium, we recommend Seachem Equilibrium.