Instead of using dirt, toxic chemical solutions or fertilizers to grow plants, aquaponics uses highly nutritious fish effluent that contains all the required nutrients for optimum plant growth. Instead of discharging water, aquaponics uses the plants and the media in which they grow to clean and purify the water, after which it is returned to the fish tank. This water can be reused indefinitely and will only need to be replaced when it is lost through transpiration and evaporation. Two primary methods of aquaponics growing are most widely in use today.
- The raft based aquaponics growing system uses a foam raft that is floating in a channel filled with fish effluent water that has been through filtration to remove solid wastes. Plants are placed in holes in the raft and the roots dangle freely in the water. This method is most appropriate for growing salad greens and other fast growing, relatively low-nutrient plants.
- The second method is called media based aquaponics because plants are grown in inert planting media (gravel, expanded clay pellets, coir, etc.). The media provides both the biological (ammonia based waste) and mechanical (solid waste) filtration, so requires far less maintenance than raft-based systems. Large, fruiting plants are also grown much more successfully in media based systems than in rafts.
- The third method is called hybrid aquaponics, which is a combination of the two. The media beds become the pre-filter for the solid waste before the water enters the raft systems. This hybrid system style is the focus of The Aquaponic Source’s AquaBundance systems because it provides planting flexibility, high productivity and low maintenance.