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About Aquaponics

In an aquaponics system, the fish provide nutrients in the form of their “waste,” or excrement. This waste contains nitrogen in the form of ammonia along with a variety of nutrients like phosphorus and potassium. Nitrifying bacteria that live in the gravel in the fish tank and on the tank walls convert the ammonia first into nitrites and then to nitrates. The water in the tank, which contains ammonia, nitrites, nitrates, phosphorus, potassium, and other micronutrients, is continuously pumped into a grow bed where the plants are located. The plants remove the nutrients from this water, and nitrifying bacteria in the grow bed clean the water by converting excess ammonia into nitrates, which plants use to grow. The clean water is then sent back into the fish tank. The grow bed and plants act as a biofilter, cleansing the water so that the fish remain healthy. In aquaponics, the fish, plants, and beneficial bacteria all depend on each other to live. This amazing and SIMPLE method of growing organic food is strongly gaining popularity worldwide. With global food prices rising, economic uncertainty, droughts and diseases attributable to poor diet all becoming more common it is no wonder that aquaponics has become such an attractive alternative for those who want to grow more, healthier food in less space, faster at a lower cost, while minimizing their environmental footprint. Aquaponics can be defined as as a farming technique to produce sustainable food through the symbiotic relationship between fish and cultivation of plants in water. It is combining two separate aspects of farming namely, aquaculture and hydroponics into a single system. Aquaponics is therefore, blending two agricultural methods to create a superior and environmentally friendly way of growing organic food. Once the symbiotic cycle is initiated, the water in the tank remains clean with balanced ph levels and requiring very little recycling. Furthermore, it requires very little additional water to make up for plant absorption and evaporation due to recycling. With water, fish feed and electricity to pump water between subsystems as the only three inputs, this extensive farming system has a great edge over the conventional farming that consumes a lot of water, fertilizers, pesticides, care, etc. Conventional fertilizer is made from decaying biological matter and wastes so by using live fish to produce waste you are eliminating the need for fertilizers. Fish also produce ammonia in their waste which is high in nitrogen, an element essential for plant nutrition and growth. The fish are also can be harvested and either sold or eaten. The choice of fish is varied but we use Tilapia because of their quick growth and the fact that they keep reproducing until they have no more room in the tank making a constant crop available. We have found a variety that do well in cooler water as well, which is important since usually Tilapia prefer very warm water. There are two primary methods that we use for growing food aquaponically: the raft method, and the media-filled bed method. The raft method grows plants on boards (rafts) in tanks separate from the fish tank, where the raft supports the plants and the roots of the plants sit directly in the water. Water flows constantly from the fish tank, through filters, through the rafts, and then back to the fish tank. The extra volume of water in the raft tank is a benefit as it provides a buffer for the fish so they are not stressed by possible water quality problems. In the media-filled bed method, the plants grow in a box filled with a growth medium, such as perlite or gravel, on top of the fish tank. Water from the fish tank is pumped into the box and then percolates through the growth medium and back down into the fish tank. The kinds of plants that can be grown depend on the density of fish in the tank. Lettuce and herbs require low to medium nutrient levels, so they don’t need a high density of fish, while fruiting plants like tomatoes have higher nutrient requirements and therefore need a higher density of fish to supply their nutrient needs. Lettuces, leafy greens, herbs, medicinal herbs, squash, peas, cabbages, eggplants, zucchini, kale, Brussel sprouts, peppers, broccoli, spinach, cauliflower, Swiss chard, and many types of bush beans. In addition, flowering plants such as tomatoes, all types of berries, any herbs, and cut flowers as well as small root vegetables, such as beets, radishes, leeks, green onions, and garlic. Larger units allow growth of all of the vegetables, vine vegetables or flowering plants mentioned for growing in the smaller units, plus melons, papaya, figs, passion fruit, pomegranates, bananas, and even small tropical fruit trees can be grown.