Purple Up has a unique dual method approach to coralline algae acceleration:Ionic calcium: Immediately raises dissolved calcium levels in your aquarium waterTen micron aragonite: Targets the live rock surface, where it dissolves in situ (in place), delivering calcium, strontium, magnesium and carbonate right where it is neededOther Features:Iodine Replenishment: PurpleUp replenishes iodine, an essential element for coralline algae tissues that quickly becomes depleted in closed systems.Easy to use. One bottle of Purple Up replaces the typical multi-product recipe for successful coralline algae growth favored by advanced aquarists.Contains Super Sea Calcium, a natural calcium derived from pristine tropical oceans.Treats up to 4730 gallons.