The system
An aquaponic system consists of two basic components: a fish rearing area and a plant growing area both of which are connected by a pump and pipe work. In fact it functions rather like a blood circulation system. The water is the ‘blood’ which contains waste from the fish tank and is pumped (the heart) around to the grow beds (lungs) where the waste is converted into a useful product and the cleaned water returned to the fish.
.jpg "Tank stocked with tilapia")
Fish tank
For a small system, one fish tank will suffice, however if your system is larger or you want to have a range of different sizes of fish, more tanks can be incorporated. The tank can be made out of a range of materials such as IBC’s, plastic tubs or even make use of a quality pond liner. What ever material you use it must be fish friendly.
Grow bed systems
There are three basic approaches to growing plants in an aquaponic system:
- Gravel filled / expanded clay beds – plants are grown in these beds which are continually being dosed with fish waste water while at the same time are well aerated.
- Deep Water Culture (DWC) or floating raft – the plants are grown in small baskets which are suspended on a floating foam raft in a tank filled with circulating (aerated) water from the fish tank.
- Nutrient Film Technique (NFT) – plants are grown in small pots which are suspended over a narrow channel of running waste water from the fish tank.
These two later approaches are used more widely in commercial projects..jpg "Demonstration system")
For small scale systems such as for home use, we recommend using expanded clay beds for a number of reasons:
- No pre-filtering of water is required
- The widest range of plants can be grown in grow beds from lettuce to aubergines, from tomatoes to water cress
- There are options to integrate with other approaches such as NFT or DWC systems
