Aquaponics systems are farming systems that combine traditional fish farming (aquaculture) with hydroponic cropping techniques.  If you’ve never heard of aquaponics or aren’t sure how the systems work, below is a great primer on the makeup of a commercial system produced by Purdue University.  Check out the video and then read on to learn more. To learn more about aquaculture in general click here.

Traditional aquaculture suffers from populations that are unnatural in concentration. These concentrations of fish or shellfish exist in a closed loop system.  While feed is continuously added to the system, sophisticated filtration systems are necessary to clean the water of effluents (fish waste) or the water quickly gets out of balance and becomes toxic to the animals in the tanks.

Recycling Waste

Aquaponics systems build up waste and biofilm which is rich in ammonia (NH3).  In nature, the nitrogen cycle utilizes nitrifying bacteria to convert ammonia into nitrite and nitrate (No2 and NO3).  Nitrate is a form immediately available use by plant roots as food.

In an aquaponics system, farmers create a holding tank or system which allows bacteria to take the fish waste convert it into a plant-available form.

The resulting nutrient rich water is filtered and fed to a hydroponic system that feeds the plants’ roots in the system.  Hydroponic systems work by putting soluble nutrients into the water in the system.  The plants roots are exposed to this watered down liquid fertilizer bring up the nutrients to help build amino acids, proteins, phyto-nutrients, aromatic compounds and other compounds that enhance the health and vitality of the plant.

Aquaponics is interesting in that it takes a weakness of traditional fish farming and turns it into a strength by taking the waste from the aquaculture and feeding it to plants as nutrients.

Typical Aquaponics Setup

aquaponics system

  1. A typical low-energy aquaponics setup starts at the highest point with the fish tanks.
  2. The fish tanks drain out to a settling tank.  The settling tank is used for draining off the particulate matter out of the rearing tanks.
  3. Next is a biofilter.  The biofiltration system is where bacteria that are capable of converting the ammonia in the water to nitrates are grown.
  4. Once the nutrient rich water has been biofiltered, it is pumped into the hyrdroponics system
  5. Collection tank is the lowest point in the system where the resultant off-flow can be treated for pH or nutrients before being pumped back up and into the fish farming tank.