ESV Calcium Hydroxide, also known as Kalkwasser Powder 14 oz. (400 grams), offers a reliable solution for maintaining optimal calcium concentration and alkalinity in closed marine aquarium environments. This high-quality product serves as a direct source of calcium for calcifying organisms, supporting their growth and health. Additionally, the hydroxide ions present facilitate the conversion of dissolved CO2 into bicarbonate and carbonate ions, which are essential for the well-being of marine organisms. With its exceptional purity and adherence to standards set by the American Water Works Association and Water Chemical Codex, ESV Calcium Hydroxide ensures the integrity of aquatic ecosystems in marine aquariums.