Seachem Onyx 7kg
Onyx™ is a specially fracted natural substrate for the aquarium. Onyx™ is suitable for any marine or freshwater environments and is ideally suited for Cichlid environments. Onyx™ is most effective when used alone as an integral substrate bed, but it may be mixed with other gravels or sands. Onyx™ is not chemically coated or treated but does have a slight buffering capacity.
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 7,000 cm3 (425 cu. in.).
Although it is pre-washed, because Onyx™ is a natural product, it may become dusty in transit and require rinsing before use to remove any residual dust.
Units=mg/kg, source: Plasma Emission Spectrometer, EPA Method 6010, Univ. of Georgia Chemical Analysis Lab