Onyx Sand, 7 kg / 15.4 lbs
Onyx Sand is a specially fracted, stable porous gravel for the natural planted aquarium. 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).