Onyx Sand™ is a naturally dark gray sand that perfectly complements and enhances the appearance of any aquarium. It supports optimal KH levels for freshwater planted aquariums. Although ideally suited to planted aquaria, it may be used in any aquarium environment. Onyx Sand™ is most effective when used alone as an integral substrate bed, but it may be mixed with other gravels. Gravel modifiers such as laterite are not necessary. Onyx Sand™ is not chemically coated or treated, and as a carbonate rich sand, it has a slight buffering capacity that may raise pH by 0.1 - 0.5 pH units (depending on source water characteristics). Onyx Sand™ is good for the life of the aquarium and need not be replaced. Set-upAlthough it is pre-washed, because Onyx Sand™ is a natural product, it may become dusty in transit and require rinsing before use to remove any residual dust. When adding water to aquarium, fill slowly to avoid disturbing Onyx Sand™ substrate bed. Place a bowl in the aquarium and add water directly to the bowl, allowing water to overflow softly on to the gravel bed. Initial cloudiness is normal. To remove cloudiness, use mechanical filtration (such as filter floss). Use Clarity™ to accelerate clearing.