Onyx Gravel is a specially fracted, stable porous clay gravel for the natural planted aquarium. Its appearance is best suited to planted aquaria, but may be used in any aquarium environment. Being carbonate rich, Onyx Sanda 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 Sanda 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 Sanda is not chemically coated or treated and will not alter the pH of the water. 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 Sanda bed is not disturbed. Slight initial cloudiness is normal and will clear rapidly (2Ð12 hours). To shorten the cloudiness period use Claritya in conjuction with mechanical filtration (such as filter floss).