The way aquaponic systems are built are endless. The two parts that are the same are the fish tank and a plant bed. Some of the differences include filtration techniques, plumbing, the type of plant bed, growing medium, and the frequency of water and aeration. Some of the more popular aquaponic methods emerging in the industry are methods based on a hydroponic system design, and raising fish for filtration.
The Raft Method
The raft system method is the first of our easy aquaponic systems. The raft system is also known as deep channel, float and deep flow. The plants are grown on rafts made from Styrofoam boards that float on the water. The rafts are usually in a tank separate from the fish tank. 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. The beneficial bacteria live in the raft tank and throughout the system.
The water in the raft tank provides a buffer for the fish, reducing stress and potential water quality problems. This is one of the greatest benefits of the raft system. Plus, this method has been improved for over 20 years. The raft system is a well developed method that allows for high plant production per square foot. Commercial raft systems can cover large areas, best utilizing the floor space in a greenhouse. Vegetable seedlings are best placed on one end of the raft tank. The rafts are pushed forward on the surface of the water over time and then the mature plants are harvested at the other end of the raft. Once a raft is harvested, it can be replanted with seedlings and set into place on the opposite end. The optimizes floor space, which is especially important in a commercial greenhouse setting.
The NFT (Nutrient Film Technique) Method
The second setup is hydroponic NFT (Nutrient Film Technique), which is a method in which long narrow channels are used to grow the plants. A thin film of water continuously flows down each channel, providing the plant roots with water, nutrients and oxygen. As with the raft system, water flows continuously from the fish tank, through filtration components, through the NFT channels where the plants are grown and then back to the fish tank. In NFT, a separate bio filter is required, however, because there is not a large amount of water or surface for the beneficial bacteria to live. 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. NFT aquaponics shows potential however, it is used less than other aquaponic methods.
The EBB (Flood and Drain) Method
Hydroponic EBB and Flow is the third method of aquaponic systems. EBB and Flow or Flood and Drain uses media filled beds that are periodically flooded with water from the fish tank. The water is drained after the water level rises above the bell siphon and flows back to the fish tank. All waste, including the solids, is broken down within the plant bed. Sometimes worms are added to the gravel-filled plant bed to enhance the break-down of the waste. This method uses the fewest components and no additional filtration, making it simple to operate and naming it one of the best aquaponic system methods. The plant production is less than the two methods described above. The media-filled bed is often used for hobby applications where maximizing production is not a goal.
The Aeroponic Method
Another method that can be use with aquaponic systems it the basic principle of aeroponics. Your vegetables and plants are suspended in a closed or semi-closed environment by spraying the plant’s dangling roots and lower stem with an nutrient-rich fish water. The leaves and crown, often called the “canopy”, extend above the the growing container. The roots of the plant are separated by the plant support structure. Many times closed cell foam is compressed around the lower stem and inserted into an opening in the aeroponic chamber, which decreases labor and expense; for larger plants, a trellis structure is used to suspend the weight of your crops.
Ideally, your system is kept free from bugs, pests and disease so that the plants may grow healthier and more quickly than plants grown in a medium or the soil. However, since most aeroponic environments are not perfectly closed off to the outside, pests and disease may still cause a threat. Controlled environments advance plant development, health, growth, flowering and fruiting for any given plant species and cultivators.