Seachem Onyx Sand is a naturally dark grey 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. Seachem 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). It 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 7kg of Seachem Onyx Sand occupies a volume of approximately 4,250cm3. To determine your desired volume multiply tank width by length by desired depth. This bag is sufficient for about a 3.5cm deep bed in a typical 40L tank.

Key Features:

• Premium natural sand for the planted aquarium
• Good for the life of the aquarium
• Supports optimal KH levels for freshwater planted aquariums
• Rich in carbonates

Directions:

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).