Brightwell Aquatics Calcion - Liquid Calcium Supplement for Reef Aquaria 2L / 67.6oz Highly-concentrated ionic calcium solution. l Increases the concentration of calcium in marine aquarium water to provide corals and other reef-bui Is ionic rather than chelated, and contains no unwanted organic material such as EDTA, gluconate, or Over 50% stronger than most competing products. l Free of phosphate, silicate, and organic material. l