The complete Aquaponics system starts with fish. Tilapia are the most common aquatic component throughout most of the US. As the fish eat food, namely Duckweed, Nitrogen rich waste is excreted. Nitrogen is great for plants, but not so great for fishes. At a high enough concentration, Nitrogen can be toxic to the fish.
The first step in breaking down the Nitrogen rich waste is exposing the water to bacteria. Not all bacteria is bad. The bacteria we are looking for works in the next component of the Aquaponics system, the grow beds. When the water meets these friendly bacteria, the Nitrogen serves as a tasty bacteria snack. The byproduct of the bacteria munching is Nitrites and Nitrates.
Next comes the Grow beds. Grow beds may or my not contain rocks for the food to grow. Leafy crops such as lettuce do well floating in mesh bags suspended in the bed. Other plants such as Tomatoes grow well in the rocks if the system’s water level is varied so that the roots can dry out between watering. The roots of the plants absorb the Nitrates. The roots also work to filter the water by absorbing other nutrients and minerals from the water.
The water in the system requires little in the way of filtration, if sufficient grow beds are present. In fact, the Aquaponics number one problem plaguing DIY Aquaponics projects is a lack of growing plants in the system.
Air is the final component. Air pumps are often required to supply oxygen to the fish. The amount of available oxygen in the water directly affects the fish’s ability to grow. When in doubt, air it out!
Getting fish to grow in water is the easy part of Aquaponics or Aquaculture. Keeping the water quality high is another issue. It’s hard to over-plant when it comes to Aquaponics. In fact, the challenge is to have enough of a growth area (grow beds, etc) to adequately remove the the Amonia abd byproducts from the water.
Try to find fish growing containers with lots of surface area for oxygen. Try to build grow beds with at least 2 to 4 times the surface area of the pond or tank.