Aquaponics

Aquaponics is a combination of fish-keeping in aquaculture and plant cultivation in hydroponics.

It is a closed-cycle-system for water and nutrients which is run automatically.

Fish-keeping in aquaculture
One component of aquaponics is the keeping of fish in containers, fishtank or ponds. According to specific requirements of the fish or the fish-keeper (market) different species can be bred in the system.

Often Tilapia or Oreochromis are kept as fast-growing fish with low demands. They can be fed with algae, vegetables and prepared fish feed, but in temperate climates the tanks have to be insulated and heated in winter.

The water is continuously pumped for irrigation of the growbeds or a flood and drain system is used to flood the growbeds.

Plant breeding in hydroponics
Another component is the breeding of plants in an anorganic substrate, similar to hydroponics but without a chemical nutrient solution.

The crop plants mostly grow in growbeds, open, irrigated containers containing the substrate. Cultivation in Nutrient Film Technique or Deep Water Culture is also possible.

The outflow of the growbeds runs back into the fishtank.

Microorganisms as a system component
The gravel or sand on the bottom of the fishtank and the substrate of the growbed contain nitrifying bacteria in biofilms, that converte the ammonia coming from the fish secretions to nitrites and finally nitrates.

Nitrates are then available to the plants that use them as nutrients to grow and thus remove them from the water.

Aquaponik