Seachem Onyx Sand 7kg

Onyx Sand is a specially fractured, stable porous clay gravel designed for the natural planted aquarium. Its striking dark appearance enhances planted aquascapes, while its versatile composition makes it suitable for use in virtually any freshwater aquarium environment.

Naturally carbonate rich, Onyx Sand provides a unique advantage for aquatic plants capable of utilizing bicarbonates, helping support healthy growth and long-term vitality. It is most effective when used alone as a complete substrate bed, but can also be mixed with other aquarium gravels to achieve your desired look and layout. Gravel modifiers such as laterite are not necessary.

Onyx Sand is not chemically coated or treated and will not alter the pH of the water, ensuring stable water chemistry for fish, plants, and invertebrates.

Although pre-washed for convenience, a light rinse before use may help remove residual dust. To minimise cloudiness during setup, fill the aquarium slowly and disperse water gently to avoid disturbing the substrate bed. Slight initial cloudiness is normal and typically clears within 2–12 hours. For faster clarification, use Clarity in conjunction with mechanical filtration such as filter floss.

Key Features:

• Specially fractured, porous clay gravel for planted aquariums

• Carbonate rich to support plants that utilise bicarbonates

• Ideal as a standalone substrate or mixed with other gravels

• No laterite or additional modifiers required

• Not chemically coated or treated

• Will not alter aquarium pH

• Minimal clouding with proper setup

Create a strong, natural foundation for lush planted aquariums with Onyx Sand.