Aquaponics is an exciting style of growing that combines the cultivation of fish with the art of growing plants. The fish waste provides nutrients for the plants while the plants clean the water for the fish. Typically, in fish production, the waste becomes toxic for the fish, so water must be exchanged to provide the right conditions for fish health. In a hydroponic garden, the nutrient rich water solution becomes depleted and needs to be exchanged. When you combine aquaculture and hydroponics, both growing systems solve the other ones water waste issue as well as increase efficiency of space, maintenance, and inputs.
How It Works
~ Nitrogen Cycle: Fish produce waste in the form of ammonia. Bacteria convert the ammonia into nitrite and then into nitrate. Both ammonia and nitrite are toxic to fish at high concentrations and not the right source of nitrogen for plants to grow. Fish can handle much higher concentrations of nitrate however, and it is most plants preferred source of nitrogen.
A media bed is an Aquaponic System that utilizes media such as expanded clay as a foundation for root growth. Water is pumped into a media filled grow bed and then allowed to flow back to the fish tank. This is a hydroponic growing method called Flood and Drain. This timed flow of water allows for the plants to have a consistent supply of nutrient rich water while maintaining high oxygen levels in the root zone.
As the water rises and falls throughout the media, fish waste becomes trapped and slowly settles to the bottom layers of the grow bed. The media filters the solids and colonizes bacteria on its surface area. This alleviates the need for a bio-filter or clarifier to be added to the system. As a media bed matures, worms may be added to help further break down solids and waste in the system into condensed slow released nutrients. This allows us to avoid cleaning the media in a balanced system.
Benefits of Media Beds
~ Plant Support
~ A home for composting worms
~ Mineralization of Solids
~ Ease of Use
A raft is an Aquaponic System based on a hydroponic growing method called Deep Water Culture or DWC. In a raft system, roots are grown directly in the water while the plant floats on the surface in a “raft”. The raft can be made from sheets of Styrofoam or suspended in a fixed structure. Oxygen is pumped into the system to allow for proper root health. The main benefit of growing in a raft is the water added to the system. More water allows for more stability by buffering temperature, pH, and nutrient load. Another benefit is that a raft is relatively inexpensive to set up without the added cost of media to fill the grow space.
The downside to the raft system is that there is not enough surface area for the beneficial bacteria to colonize. A bio-filter is necessary to convert toxic fish waste into healthy plant nutrients. Also, a clarifying filter is necessary to keep waste solids from building up on the roots and within the system. Creating a hybrid system by adding a raft to an existing media bed is a great way to avoid the use of a bio-filter or clarifier. The expanded clay in a media bed acts as a bio-filter and a solids remover.
Creating a hybrid system by adding a raft to an existing media bed is a great way to avoid the use of a bio-filter or clarifier. The expanded clay in a media bed acts as a bio-filter and a solids remover.
A Hybrid Aquaponic System is the combination of a Media Bed and a Raft system. Both the Media Bed and the Raft system have advantages and disadvantages. When we combine the two, we capitalize on the assets of both styles and remove some of the disadvantages.