Essentially, there are a couple main types of aquaponics system design – media-filled bed, deep water culture (or raft) and the nutrient film technique.
Media-filled beds can be considered to be the most common and simplest aquaponics design. This is typically the design adopted by most backyard aquaponics gardeners. In this design, plants are grown directly in a media-filled grow bed. The growth media used can be expanded clay or gravel. Water rich in nutrients (ammonia-rich waste and nitrates) are pumped from the fish tank to the media-filled grow bed. The media-filled bed aquaponics setup can be further subdivided into 2 configurations – continuous flow system and the flood and drain system (also known as ebb and flow system), based on the way the water is being re-circulated.
Deep water culture or raft is predominately used for commercial system as it is relatively inexpensive to set up and a wide variety of leafy vegetables and herbs can be grown. Holes are drilled on floating boards or foam rafts for the pots. The plants are then grown in these pots with their roots immersed in the water.