Onyx Sand is a naturally dark gray sand that perfectly complements and enhances the appearance of any aquarium. It provides not only iron and other minerals but supports optimal KH levels for freshwater planted aquariums. Being carbonate rich, Onyx Sand provides an advantage to any plants able to utilize bicarbonates. 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 but does have 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. Although pre-washed, it may be rinsed before use to remove residual dust. Dust can also be minimized by filling aquarium slowly and dispersing water so that the Onyx Sand bed is not disturbed. Slight initial cloudiness is normal and will clear rapidly (212 hours). To shorten the cloudiness period use Clarity in conjuction with mechanical filtration (such as filter floss).