Seachem Onyx Sand 7kg
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.