The overall setup of an aquaponics system is not that complicated. There are just a few major components required. Of course, there will be huge differences between a home hobbyist’s system and a large-scale commercial operation. Even in the latter case, however, a close examination will show that the commercial system is still based on the same basic building blocks, albeit they have been “ramped up” a bit.
A Closed System
The key to aquaponics is that it is a nearly closed system. The plants clean the water for the fish while the fish provide nutrients essential to healthy plant growth. It is a balanced, sustainable environment, and a symbiotic relationship. Even water rarely needs to be added to or removed from the system.
The main thing that is added into the system on a regular basis is fish food. The fish, plants and microbes work together to turn that fish food into a steady supply of vegetable crops and, if edible fish are used, fresh fish.
Components of an Aquaponics System
The chief components that must be present in any aquaponics system are:
- Rearing Tank – This is a tank or tanks where fish are raised.
- Solid Waste Removal – This is a unit that catches uneaten food and fish waste and settles out the fine particulates that amass over time
- Biofilter – This is where the microbial activity takes place. Nitrification bacteria live and grow here. Their job is to convert the ammonia produced by the fish into usable nitrates
- Hydroponics Subsystem – this is where the plants are grown
- Sump – The lowest point in the system. This is where the water naturally flows to, and so must be pumped back into the rearing tanks.
For example, it is common to see the solids removal, biofilter and hydroponics pieces all combined into a single unit.
There are other possible components that may be included, depending on what kind of aquaponics system you are using. These variable components include filtration, plumbing, the type of plant bed, and the amount and frequency of water circulation and aeration.
Aquaponics Design Configurations
There are three main configurations in use right now. They are in decreasing order of popularity, commercially speaking:
In this kind of system the plants are in a separate tank from the fish. The bacteria, however, live in the raft tank. Because of the large volume of water used to fill the tank initially, there is less risk of stress on the fish due to low water levels.
Typically, a new crop of plants is placed into new rafts each week at one end of the system, pushing all the other rafts forwards towards the other side. And then the plants are harvested at the far end each week providing a continuous source of fresh crops.
NFT (Nutrient Film Technique)
Plants are grown in long narrow channels. A thin film of water flows down each channel. This provides the roots with the water, nutrients and oxygen they need. This water is continuously circulated from the fish tank.
The fish have their own tank, which ensures they have a buffer of water to reduce stress. In the NFT system the bacteria also have a separate biofilter tank. This is needed because the level of water in the channels is not sufficient to support their population.
In this system the plants do not grow in water alone. Instead they are planted in a soilless growing medium. Usually something like gravel or perlite is used. This bed is flooded with water from the fish tank.
Waste accumulates in the bed over time, but is broken down there as well to provide further nutrients for the plants. Worms are sometimes added to the media to aid in this process.
This system has the fewest components and requires no additional filtration. It is also the simplest to operate. On the other hand it is also the least productive. Fish and crop growth rates are not as fast, making this unpractical for commercial operations. It is ideal, though, for the hobbyist and anyone who does not need to maximize their food production.
The term ‘nitrification’ describes the process of converting the fish waste into usable nitrates.
Fish release ammonia into the water as a natural byproduct of life. They “exhale” in through their gills and they excrete it as waste. Over time the ammonia would build up and kill the fish. This is why, when you had goldfish as a kid you had to clean out the fish bowl.
Microbes in the aquaponics system perform the critical work of converting the harmful ammonium into a different form of nitrogen – nitrates. Plants can readily absorb and utilize nitrates, providing them with the essential nitrogen they crave.
If all of this seems complicated to you, don’t worry. There are products on the market you can purchase that walk you step-by-step through the process of building your own aquaponics system. They provide detailed plans and instructions, and much planning has gone into determining the right sizes and shapes of each component as well as how to set them up.
If you aren’t much of a do-it-yourselfer, there are even kits you can buy. A kit will certainly be more expensive, but you’ll be up and running in no time and you’ll quickly make back the costs through what you save from your grocery bill.