There are many different configurations of aquaponic systems. The components common to every aquaponic system are the fish tank and a soil-free plant bed. The variables include filtration, plumbing, the type of plant bed and the amount and frequency of water circulation and aeration.
There are three main growing techniques that can be implemented in Aquaponics: Media Based, Nutrient Film Technique (NFT), and Deep Water Culture.
Media Based: The media based method consists of growing the plants in a large container filled with media, which can range from gravel to perlite. This method has the fewest components, as the solid waste is broken down throughout the media, removing the need for an extra buffer filter, thus providing both the biological filtration (conversion of ammonia to nitrates) and mechanical filtration (removal of solid wastes) in the same system. Large fruiting plants do really well in addition to leafy greens, herbs and other varieties. However, this system does not produce a maximum output of plant growth.
Nutrient film technique: The Nutrient Film Technique is more widely used for hydroponics. However in some cases, it can be used for aquaponics as well. It involves growing the plants in narrow channels, allowing for continuous, thin flow of water, which results in continued supply of nutrients and oxygen. In NFT, a separate bio filter is required. In addition, the plumbing used in a hydroponic NFT system is usually not large enough to be used in aquaponics because the organic nature of the system and “living” water will cause clogging of small pipes and tubes. This method requires constant maintenance and is suitable for a very small set of plants, lest the roots clog up the gutters/pipes.
Deep water culture: The Deep Water Culture method, also known as the raft method, involves cutting holes in a raft to secure the plants and to also allow the roots to be suspended in the water. Water flows continuously from the fish tank, through filtration components, through the raft tank where the plants are grown and then back to the fish tank. In a commercial system, the raft tanks can cover large areas, best utilizing the floor space in a greenhouse. The Deep Water Culture Method provides an excellent model for sustainable food security.
At forthesalad by Kia farms, we have implemented the raft and the NFT systems to optimize our space.