Using Gravel in Aquaponics Systems

Gravel is essential for fish tanks when using an aquaponics system. Aquaponics systems are designed to keep fertilization as natural as possible. To achieve this, fish waste is processed by bacteria. Gravel harbors beneficial bacteria, whose role is to keep fish healthy, and to produce nitrates for optimum plant growth. Gravel should be the appropriate size for the fish that are being housed in the tank. Avoid gravel with sharp edges to reduce injuries to fish.

Bacteria and Gravel

Bacteria helps to complete the nitrogen cycle, which is needed for robust plant growth. Gravel houses two beneficial types of bacteria that work together to produce nitrates for fertilization of plants. Fish waste breaks down into ammonia. The ammonia is consumed by nitrosomonas bacteria, which then converts the ammonia to nitrites. Nitrites are then consumed and converted to nitrates by nitrobacter bacteria.

Gravel for Aquaponics

When choosing gravel for an aquaponics system, make sure that the gravel is safe to use with fish. Consider the size of the gravel, if it is too small, fish can ingest it, mistaking it for food. Pea gravel comes in varying sizes and is a popular choice for fish tanks. Always rinse gravel thoroughly before placing into tanks. Not too much is needed, a layer of a couple of inches should be sufficient.