Seachem Onyx Sand

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Seachem Onyx Sand is a naturally dark grey substrate that really enhances live planted aquariums, boasting an optimal KH level for freshwater plants too.


  • Onyx Sand 7kg
    code: 20953 In Stock (Only 5 left!)

Product Information

The Onyx Sand is ideally for live planted freshwater aquariums, as it supports optimal KH levels plants. 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 could also be mixed with other gravels.

Onyx Sand is not chemically coated or treated in any way, and as a carbonate rich sand, it has a slight buffering capacity that may raise pH by 0.1 - 0.5 pH. Onyx Sand is good for the life of the aquarium and need not be replaced.

Although the Onyx Sand is pre-washed, this natural product will often be dusty from transit, and may require rinsing multiple times. When adding water to aquarium, fill slowly to avoid disturbing Onyx substrate 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). You could use Seachem Clarity to accelerate clearing.

Please Note: The Seachem Onyx needs a lot of rinsing and preparation, and it is not suitable for a soft water setup!

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