We give you the lowdown on setting up an aquaponics system at home.
Aquaponics combines aquaculture and hydroponics to produce fish and plants in one integrated system, creating a symbiotic and mostly self-sustaining relationship.
Combining fish and plants isn’t a new concept, with its origins dating back several millennia. Asia’s rice paddy farming systems is an example.
Aquaponics today borrows and combines methods primarily developed by the hydroponics aquaculture industries, along with new ideas from the innovative DIY online community.
How setting up an aquaponics system works
The basic principle of synergy involved in aquaponics is the requirement of clean water to promote the healthy and fast growth of fish, and the need and ability of plants to use nutrients from the water to grow.
One of the most critical aspects in this relationship between plants and fish is the diverse microbial community which transforms fish wastes into forms of nutrients more easily used by plants for growth.
In the simplest arrangement, you will need a tank for fish and a trough for plants. Given that plants require physical support for their roots to extend into, some kind of growing substrate is required in the trough.
Often quarried gravel, scoria or manufactured clay pebbles are used. More advanced growers tend to use a raft system. A raft usually floats on the water, allowing the plant roots to hang into the water.
The substrate is often the most important design feature as it is vital in supporting and promoting the microbial health of the system. Microbes coat the gravel, so as the water is recirculated between the fish tank and the planted trough, the fish wastes are filtered which produces clean water for the fish.
Why set up an aquaponics system?
Plant growth in aquaponics is very quick, with high productivity from a small area. This is the same for fish growth, with people easily growing 10kgs of fish for each cubic metre of water in a simple backyard system.
For the backyard enthusiast or school environment, aquaponics as an educational tool can cover the most basic concepts of biology and ecological systems to the more complex interactions of water and microbial biochemistry.
These systems can also be designed to mimic local aquatic ecosystems and make for fantastic observation. On a practical level you can explore construction, plumbing and the tricky balance of growing fish and vegetables simultaneously. It is very much a multi-skilled project!
Like all gardening, there is always regular maintenance, and aquaponics is no exception. However there is a certain labour of love that goes along with aquaponic growing, especially for the beginner.
The day-to-day maintenance requires fish to be fed once or twice a day, keeping an eye on fish behaviour and health to avert disease.
The system’s water level and pump need to be checked, making sure the aerator is running and supplying oxygen to the fish.
Every few days it’s time to check your water quality and adjust where needed; a crucial task. This involves a range of reasonably simple tests you can buy from an aquarium shop.
Once you get the hang of it, tasks will speed up, requiring less effort. Aquaponics for the most part requires far more attention to detail and time while you’re learning.
Is aquaponics viable?
Aquaponics offers a lot of advantages, primarily in its ability to produce vegetables and fish with a very low overall water demand.
In locations where vegetable produce has high food miles and is not produced locally, aquaponics can have a comparatively small environmental footprint. Although often it’s likely that aquaponics has a bigger environmental footprint than other types of vegetable production.
If there is sustainable local fishery, good rainfall, and fertile soil, it is likely that supporting or engaging in regular home gardening in the soil and buying fish locally (or going fishing yourself) might be more sustainable.
In most cases, aquaponics uses a reasonable amount of energy to continuously recirculate water and to provide oxygen through aeration for the fish and plants. The home grower will also need access to good quality fingerlings and fish feed to keep their systems going.