Onyx™ is a specially fracted porous substrate for the aquarium. Onyx™ is suitable for any marine or freshwater environments and is ideally suited for cichlid environments. Onyx™ is most effective when used alone as an integral substrate bed, but it may be mixed with other gravels or sands. Onyx™ is not chemically coated or treated but does have a slight buffering capacity. 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™ bed is not disturbed. Slight initial cloudiness is normal and will clear rapidly (2–12 hours). To shorten the cloudiness period use Clarity™ in conjuction with mechanical filtration (such as filter floss). To determine the number of bags required for your aquarium, please note that each bag (7 kg, 15.4 lbs) occupies a volume of approximately 7,000 cm3 (425 cu. in.).