Seachem Onyx Sand - 3.5kg/7.7lbs
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.
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 4,250 cm3 (260 cu. in.). To determine your desired volume multiply tank width by length by desired depth. This bag is sufficient for about a 3.5 cm (1.5 inch) deep bed in a typical 40 L (10 US gallon) tank.
Although it is pre-washed, because Onyx Sand™ is a natural product, it may become dusty in transit and require rinsing before use to remove any residual dust.
TIPS: When adding water to aquarium, fill slowly to avoid disturbing Onyx Sand™ bed. Place a bowl in the aquarium and add water directly to the bowl, allowing water to overflow softly on to the gravel bed. Initial cloudiness is normal. To remove cloudiness, use mechanical filtration (such as filter floss). Clarity™ clearing.