If Hydroponics and Aquaculture had a baby, what would it be called? Aquaponics!

Posted by Abel Prasad on

So… what is it?

Aquaponics is an organic way of growing plants and animals together, in a closed loop system. You use a re-circulating water system (e.g. fish tank) which flows or circulates nutrient-rich water into a grow bed where plants are grown. The plants use the fish waste as their main nutrient supply, and in return, the fish benefit as the water is then filtered by the plants. It’s a win-win situation!

Straight away you know there are immediate benefits with a system like this:

  1. No soil or fertilisers involved
  2. No pesticides or herbicides used
  3. Water can be recycled
  4. You know you’re producing environmentally-friendly and economically sustainable food

What other benefits are there?

Aquaponic systems are flexible. In today’s society, flexibility is key. These systems can be either indoor or outdoor and can vary in size. If you’re indoor, grow lights can be used (in place of direct sunlight) and if you’re outdoor, you might have a greenhouse that can protect the system from the elements (heavy rain, hail etc.).

They can be set-up in metropolitan areas, in dryer regions, or in rural communities.

You can use fresh water or salt water – this depends on the type of animal and vegetation that is being grown. You can make the system as efficient as you want, for example using up little space and not a lot of water. Your produce will be consistent all year round.

Aquaponics can be set-up in your own backyard to grow food for personal consumption, but also used commercially on a larger scale. Think of a sustainable business model that has the potential to produce high-value, good quality produce to local supermarkets or a chain of established outlets. With this said, it won’t compete with hydroponics or aquaculture, but certainly meets the needs of a niche market in natural food production.

The Different Types of Aquaponics Systems

There are three main designs generally used:

Deep Water Culture (DWC) also known as Raft system:

A more commercially-used method, Deep Water Culture or Circulation is when the plants are ‘floated’ on top of the water, allowing the roots to hang down below into the water. To float the plants, you would use a foam raft on top of the tank or you may choose to pump the water from the fish tank through channels to where the ‘floating rafts’ are holding up the plants. But bear in mind, to pump the water you will need a filtration system, and to ensure the water is sufficiently oxygenated you will need an air pump or compressor. This will allow the plants to successfully take in the nutrients.

Some of the benefits associated with a DWC set-up include the option for a simple design, maintenance is low, and you can get your system working at a high level in a short amount of time.

Image from Gardenerdy.com

Nutrient Film Technique (NFT)

Our hydroponic friends will be familiar with this technique or method. Basically, NFT is when you have a constant, thin film of water flowing down an enclosed gutter. The crops are grown in cups or pots that fit into this channel, allowing their roots to absorb the nutrient-rich water. The use of this method is also dependent on the type of plant grown, as you could imagine the larger, leafier plants will have larger root systems which will become too invasive for the gutters.

Some of the benefits of the NFT technique in aquaponics include the ease of setting up with not a lot of equipment required, the constant flow of water reduces algae and the build-up of fungus, and you can easily check up on your roots due to the shallow channels.

Some plants that you might grow are: bok choy, oregano, basil, mint, iceberg lettuce, kale and more.

Image from AquaponicsExposed.com

Media Filled

This technique simply uses grow beds/containers filled with lightweight clay balls, gravel or other type of media. The grow beds are then periodically flooded (with the water from the fish tank) and drained (back into the tank) which allows the plants to have access to the nutrients on a regular basis. Sometimes standpipes or pre-filters are implemented into the system if needed. This method is simple because it has less components and no extra filtration is required, which attracts hobbyists.

Image from Iotworld.co

Which system is best for me?

If you ask a few people about how to start an aquaponic system and which one would be best, you would probably receive different answers from each person. A good start will be to ‘seed’ your system from someone else’s (i.e. an existing system). If you can collect beneficial bacteria from aquarium water or pond filters this will help your system to be established quicker. Getting a test kit ensures you can track the cycling in your system, which means you can test pH levels, ammonia, nitrate and nitrite (depending on the kit).

What about the fish?

You can grow many types of fish that are legal and suited to the climate in Australia for example Barramundi, Trout, Catfish, Silver Perch, Murray Cod, Eels... Tilapia is most common overseas, however this is prohibited in Australia. For more information about what type of fish is allowed in Australia visit the Department of Agriculture, Fisheries and Forestry or the relevant state fisheries.

Questions? Comments?

Visit us in store or drop us an email and we’d be happy to help. We also supply all the extra components you might need for an aquaponic system – check out our range of products today!


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