Ultra-pure natural aragonite from fossil origin is a substrate for saltwater aquaria. Due to its purity, Paleo Sand is extremely bright with highly reflective properties which is an advantage for high light thriving corals. Paleo Sand is an outstanding alternative to natural coral sand and protects the environment. Before placing in the aquarium, rinse the substrate thoroughly. Features and Benefits: Ultra-pure natural aragonite from fossil origin. CaCo3 : 99,2% MgCO3 : 0,4% FeO3 : 0,035%