Samoa Pink Gravel is premium aragonite reef substrate harvested from the ocean floor, pre-washed and heat treated for convenience. Its unique composition reduces nitrates, maintains pH, and increases Carbonite hardness. Ideal for reef system tank bottoms, denitrifying anaerobic beds, culturing live sand, and extremely high surface area filter media. Samoa Pink Gravel size #2 features gravel with grain size ranging 1.5 to 2 mm.