Marine White Sand #0 is comprised of premium reef sand harvested from the ocean floor, pre-washed and heat treated for your convenience. Its unique composition reduces nitrates and does not affect the pH balance of your aquarium. Ideal for reef system tank bottoms, denitrifying anaerobic beds, culturing live sand, and extremely high surface area filter media. It will not alter the chemistry of your aquarium water. Marine White Sand #0 features grain size of 0.1 to 0.5 mm.