Seachem Onyx Sand™ – Premium Planted Aquarium Substrate (7kg)

Create a striking planted aquarium with a substrate that does more than just look good. Seachem Onyx Sand™ is a premium naturally dark substrate designed to enhance planted aquariums while helping support stable water chemistry.

Key Benefits:

• Premium natural dark grey aquarium sand
• Supports healthy KH levels in planted aquariums
• Slight buffering capacity for added water stability
• Ideal for planted freshwater aquariums
• Permanent substrate that never needs replacement

Substrate plays a key role in both aquarium aesthetics and water chemistry. A quality planted substrate helps create a stable environment while providing a beautiful natural foundation for aquascaping.

As a carbonate-rich natural substrate, Onyx Sand™ helps:

• Support healthy KH (carbonate hardness)
• Improve freshwater buffering stability
• May gently raise pH by approximately 0.1 – 0.5 units (depending on source water)

✔ Helpful for planted systems needing mild buffering support

Set up tips:

• Rinse before use to remove transit dust
• Add water slowly to prevent substrate disturbance
• Initial cloudiness is normal and temporary 

For clearing up faster use:

1. Mechanical filtration (filter floss)
2. Seachem Clarity™

If you want a premium planted aquarium substrate that combines beautiful aesthetics with helpful water chemistry support, Seachem Onyx Sand™ is an outstanding choice.