Onyx Sand" 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 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 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 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 Sand" 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).