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).

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Klarna's credit products are provided by Klarna Bank AB, which is authorised and regulated by the Swedish Financial Services Authority, with limited supervision by the Financial Conduct Authority. More information can be found here.

Newpay finance options are provided through Deko’s platform by NewDay. P.D. Aquatics Ltd, t/a Aquacadabra is an Introducer Appointed Representative of Pay4Later Ltd, t/a Deko, which is authorised and regulated by the Financial Conduct Authority (ref no 728646) and is a credit broker, not a lender. NewDay Ltd is authorised and regulated by the Financial Conduct Authority (ref no 690292) and is authorised by the Financial Conduct Authority under the Payment Services Regulations 2017 for the provision of payment services (ref no 555318). More information can be found by clicking the newpay option above, or in the Newpay FAQs.

We really want you to be happy with the product that you've received. If however, when the goods arrive they're not what you want, then no problem - we have a 60 day no quibble return guarantee. Just let us know that you're going to return the item(s) by contacting us(stating your Order Number) and complete the returns packing slip that will have been included with your delivery. This will help us to quickly identify the item that you have returned (unopened and unused) - and we'll put a refund through for you.