There are a few different options for aquarium substrate, including gravel, sand, and soil. The type of substrate you choose will depend on your personal preference and the needs of your tank. For example, sand is a good choice for plants that prefer a fine substrate, while gravel is a good choice for plants that require good drainage. It’s important to choose a substrate that is appropriate for the type of tank you have and the type of fish and plants you are keeping.

Aquarium substrate is the material that lines the bottom of an aquarium. It serves several purposes, including:

1. Providing a surface for plants to root in and grow
2. Helping to create a natural-looking environment for your fish
3. Absorbing excess nutrients and waste products, which can help to keep your tank clean and healthy
4. Providing a place for beneficial bacteria to colonize, which can help to maintain the proper chemical balance in your tank