Aquaponics is a combination of Aquaculture & Hydroponics.This means that fish and plants are grown in an integrated system, creating a symbiotic relationship between the two.
What is aquaponics?
An Aquaponic system uses the water from the fish tank to circulate through a grow bed where the plants are grown.
Nitrifying bacteria convert fish wastes into plant-available nutrients. The plants use these nutrients as their main nutrient supply. The fish also benefit from this process , as the water is filtered by the plants, giving the fish clean water to live in.
This integrated system of Aquaponics has benefits not achievable when Aquaculture and Hydroponics are done separately. Aquaculture has the problem of buildup of wastes in the water, requiring filtering systems to clean the water as well as periodic releasing of waste water into the environment. Hydroponics uses chemical nutrients that eventually build up in the water and create toxic water. This water can no longer be used in the irrigation of the plants and is disposed of into the environment.
Aquaponics takes both of these problems and turns them into solutions, as the waste in the water is used to feed the plants, therefore not requiring any chemical nutrients to be added to the system, and can have no pollution of the environment by either fish wastes or chemical pollutants.
There is currently a great deal of interest in Australia about sustainable farming practices including water use, and the degradation of our soils and waterways. Aquaponics uses less water to produce the same amount of food as conventional agriculture, organic agriculture and hydroponics.
As access to water is a critical factor for farming in any country, the use of Aquaponic systems with its low water requirement means that food can be produced in places that it would not normally be grown. Fish from the Aquaculture component of the Aquaponic system can be also harvested, providing fish in areas that do not have natural access to fish in their waterways.
Aquaponics combined with a climate-controlled environment such as a greenhouse, can produce food year round. Another limiting factor for farmers worldwide is access to fertile soils capable of producing quality food. Aquaponics does not need any soils, therefore being able to be utilised almost anywhere in the world.
|Figure 1: Healthy plant growth in a aquaponics system.|
Reduced water use – with water being a scarce resource in Australia, it makes sense to use methods that reduce the amount of water used to produce the same amount of food. As the water from the fish tank is recirculated, the amount of water lost in the system is minimal. In conventional farming, the irrigation water is pumped out onto the land, only to be lost through evaporation, percolation or runoff.
Reduced chemical use – the need for chemicals is reduced dramatically in an aquaponics system, as the nutrient is made available to the plants by the fish waste. The use of chemicals in an aquaponics system can be harmful to the fish, and can disrupt the natural interactions of the fish and their environment.
Reduces erosion by eliminating the need to plough the soil – the problem of erosion in Australia is immense, with many acres of precious topsoil being lost to water and wind erosion every year, and our waterways experiencing silt build-up.
Controlled environment reduces the need for pesticides – when an Aquaponics system is set up in a greenhouse, the likelihood of infiltration by pests is reduced dramatically.
Commercial Producer Benefits
Quality farm food production typically needs land with high quality soil and access to large amounts of water. Australia does not have much land that is classed as fertile, and the small amount we do have is expensive , therefore we need other ways of growing food that does not rely on equity. The beauty of Aquaponics is that any person can do it, regardless of their location, provided there is a supply of water. This water supply can be as simple as rainwater stored in tanks.
Reduced running costs – the cost of running a conventional horticultural farm is huge, with the cost of tractors and all the implements needed reaching into the $100's thousands. With Aquaponic systems, there is no ploughing or spraying, reducing the need for large tractors which use large amounts of diesel fuel, and also reducing the need for the farmer to spend alot of their money on synthetic chemicals.
Being exposed to chemicals is not good for us, yet we continue to use them to help grow our food. The farmer has more exposure to these chemicals as they are physically handling them in preparation of spraying. The farmer is also exposed while spraying the liquid, especially if the wind blows it back into the direction of the farmer.
Backyard Producer Benefits
The reduced water use in an Aquaponics system compared to plants grown in soil is also a benefit for backyard growers, as many cities and coastal areas around Australia now have restrictions on the amount of water they are allowed to use.
Stop the backbreaking work of digging up the soil in the vegetable patch, Aquaponic systems are generally constructed so that the plants and roots are above ground level, giving you the opportunity to plant, grow and harvest all without hardly bending your back!
An Aquaponic system set up in the backyard can help to teach kids about how plants and fish grow, and to teach them about the ecological interactions that are occurring between the fish, the plants and their environment.
The great thing about Aquaponics as a learning tool, is it also produces healthy, organic food for the family, all year round.
|Figure 2: Strawberries grown using an aquaponic system.|
Frequently Asked Questions
What is Aquaponics and how does it Work?
Aquaponics is a combination of Aquaculture & Hydroponics. Aquaponics uses the water from the fish tank to circulate through a grow bed where the plants are grown. Nitrifying bacteria convert fish wastes into plant-available nutrients. The plants use these nutrients as their main nutrient supply. The fish benefit from this process also, as the water is filtered by the plants, giving the fish clean water to live in. With Aquaponics, both the fish and the plants not only grow well, they flourish.
Is Aquaponics organic?
Aquaponics is currently unable to be certified in Australia as organic, although the process of Aquaponics is a natural interaction between fish and the plants that produces no toxic waste, and does not use any chemical fertilisers or nutrients. Both the plants and the fish contribute to the cycling process of Aquaponics, with the grower using this interaction to their benefit – the fish provide the nutrients for the plants and the plants filter the water so that the fish are able to live. Natural chemicals and the fish food are the only additives to the Aquaponics system.
Is Aquaponics a Hobby or is it a Commercial Industry?
The great thing about Aquaponics is that as well as being a growing commercial industry, its methods can also be used in the backyard by the hobbyist to grow food and fish for the family.
Aquaponics systems vary in size with the smallest being an indoor fish tank with either fish you can eat or fish that you like to watch and not eat e.g. goldfish. An Aquaponics system can be adapted to an aquarium that is already operating, or can be started from scratch.
Aquaponics systems used by the backyard grower can vary in size, sometimes taking up a corner of the backyard, and sometimes taking up the whole backyard. Aquaponics also has the potential to provide fresh food and fish to the community through community based schemes, using either backyards or public land to set up the systems.
The commercial industry of Aquaponics is growing in Australia, especially since the push towards using more sustainable ways of farming began, and coupled with the drought that much of Australia has been experiencing in the last decade. Some Hydroponic and Aquaculture businesses have converted their existing enterprises into Aquaponics systems, and other business owners have set up Aquaponics systems from scratch.
Does Aquaponics Require a Greenhouse?
A greenhouse is not an essential part of an Aquaponics system, although it provides enormous protection for the system compared to being exposed to the elements (rain, hail, wind etc.). If you live in an area where it gets cold during winter, a greenhouse is needed for the protection of the fish and plants during the colder months. Aquaponics systems can also be set up indoors, using grow lights over the plants instead of using sunlight. This system uses more power than a greenhouse system due to the cost of running the lights.
|Figure 3: Young seedlings establishing from an |
|Figure 4: Several aquaponic beds.|
What are the Benefits of Aquaponics?
- Reduced water use
- Reduced chemical use
- Reduces pesticide use when set up in a greenhouse
- Reduces erosion by eliminating the need to plough the soil
- Reduced running costs compared to a conventional horticultural farm
- Stops backbreaking work of digging the soil and weeding for the home gardener
- Can produce fish and plants for the family / grower all year round, using a greenhouse
- Compared to conventional Hydroponic growers, Aquaponics does not need to use chemical nutrients for the plants, as the fish waste provides these nutrients to the plants. This eliminates the pollution of waterways, which is usually used to dispose of the eliminated chemical water.
Compared to conventional Aquaculture growers, an Aquaponics system does not have a build-up of wastes in the system that causes the water to become toxic due to the nitrites. Aquaponics utilises this waste, with the bacteria in the grow beds converting the nitrites into nitrates, which the plants then consume as their main nutrient source.
What are the Benefits of Bacteria in the Aquaponics System?
The beneficial bacteria are an essential element of an Aquaponics system, as without its successful operation, the water would quickly become toxic to the fish. Without bacteria, plant nutrients will not become available for the plants to grow in a healthy manner, and the fish would choke in their own wastes.
The bacteria do their work by converting fish wastes into plant-available nutrients, by converting ammonia into nitrites and then into nitrates, which the plants use as their main growing nutrient. The bacteria are aerobic, and proliferate in aerobic conditions (situations where oxygen is highly available). The system has turned anaerobic when there is not enough oxygen, and smells will develop. Bacteria builds up naturally when a system is setup, or can be manually added through pre purchased bottles.
What are the Different Types of Aquaponics?
There are 3 main styles of designs in Aquaponics systems including:
- Media Based
- Deep Flow / Raft
- NFT (Nutrient Film Technique)
Media Based is the most common style of Aquaponic design used in backyard systems, Deep Flow / Raft design is used mainly in commercial situations, and NFT is the least used design in both backyards and commercial systems.
Media Based systems use gravel or expanded clay medium located in grow beds where plants are grown direct where they are sown. The grow beds are usually flooded and drained periodically, allowing water to circulate through the system on a regular basis.
Deep Flow / Raft systems are constructed with long channels which hold water at a depth of around 30-40cm depth, with boards that float on top of the water. Boards can be made from styrofoam, plastics, or anything else that you can get to float. Holes are made into the boards, and net pots are fitted. Plants are either sown directly into the net pots, or transplanted from other growing area. The plants grow with their roots always immersed in the long channel of water below the boards.
NFT systems are the least used in Aquaponics, due to its high maintenance needs, including very good mechanical filtration systems needed. Plants hang in net pots much like Deep Flow systems, but instead of a body of water always to hang into, a small amount of water is run along the base of the channel where the plants roots can access it.
Do I Require an Permits to Set up an Aquaponics System?
There are no permits needed in Australia to set up a backyard Aquaponics system. If you are looking at setting up a commercial system, you need to contact the Department of Agriculture, Fisheries and Forestry and also the relevant state fisheries department, click on each link below.
New South Wales Department of Primary Industries and Fisheries
Victoria Department of Primary Industries and Fisheries
Queensland Department of Primary Industries and Fisheries
South Australia Primary Industries and Resources
Western Australia Department of Fisheries
Northern Territory Government
Tasmanian Department of Primary industries
What are the Main Success Factors of Aquaponics?
Dissolved Oxygen - All fish require dissolved oxygen to survive. the amount of oxygen that the water can hold depends on the properties of the water, particularly temperature, with warmer water holding less oxygen. High oxygen depletion occurs shortly after feeding. Factors that will change the amount of dissolved oxygen in the system include stocking density (more fish, less oxygen), temperature (higher temperature, less oxygen), salinity of water (high concentration of dissolved salts, less oxygen) and use of air diffusers (smaller bubbles, more oxygen). Water will only absorb a certain amount of oxygen before it becomes saturated.
Water Temperature - Water temperature is critical for fish survival. A drop or rise in temperature too great can induce a state of shock, possibly causing fish deaths. Each species of fish has a different temperature range, and depending on your climate, heating or cooling of the water may be needed to keep fish happy. In cold locations, if water is not heated over winter the fish will enter a type of suspended animation, where they will not eat or swim too much, until water warms up again.
pH - The pH is a way of expressing the number of H+ (Hydrogen) ions in water. Pure water (distilled) has a pH of 7 which is classed as neutral. The pH scale ranges from 0 -14, anything below 7 is acidic, anything above 7 is alkaline. The optimum range for Aquaponics system pH is between 7 - 7.5, which is a compromise between optimal ranges for the fish, plants and bacteria.
Water Hardness - Water, depending on its source can have many dissolved compounds. Large differences occur between the hardness of rainwater (slightly acidic) and bore water (generally much more acidic), due to bore water traveling through the ground and dissolving many compounds, particularly carbonates. The more of the dissolved material in the water, the harder the water is. The hardness is used to show the total concentration of calcium and magnesium ions in the water, and is measured in parts per million (ppm) of calcium carbonate. Soft water has 0 - 55ppm, very hard water has 211 - 500 ppm.
Nutrients - Both macro nutrients and micro nutrients are essential for the plants in an Aquaponics system. Most of these nutrients come from the fish waste, which has been produced from the ingredients of the fish food. Plants will still grow with little nutrients, but their look and taste will be compromised - fruiting plants will struggle to produce good fruit, and plants will be more likely to suffer from pest and disease problems.
Water Testing - Testing of your Aquaponics water is essential to know how your system is performing, and if records are kept of each test result, you are able to look back over time to see how much specific levels have changed. Keeping records also gives a good indication of what is a balanced system, it is easy to look back and collect info together to create graphs of your system performance.
What Source of Water can I use in my System?
As with all water used in Aquaponics systems, it has to be free of toxic chemicals, and if possible, have little or no suspended solids (clay). Water that is clear will make it easier to observe the fish, giving you a clear view of what is happening in the fish tank. Clear water allows you to monitor any buildup of wastes at the base of the tank, as well as letting you see that the fish are eating all of the food given to them.
If using chlorinated water, chlorine must be removed before water can be added to the system. Chlorine can be removed from water by either using a filtration unit, exposing the water to air and sunlight for several days, or using water additives that neutralise the water.
Can I use Fresh or Salt Water?
Both freshwater and saltwater can be used in Aquaponics. Freshwater is the most common used water, there are a large range of plants that use freshwater. When using saltwater, plant selection is limited, and is generally used to grow products such as kelp (seaweed).
What Type of Plants can I Grow in an aquaponics System?
There have been many studies into the types of plants that can be grown in an Aquaponics system, including leafy green vegetables, vine plants, fruit and fruit trees, flowers and fodder. The cost and turnover time of each crop varies dramatically with leafy greens being able to be produced in a few months, with root based plants and fruit trees taking considerably longer.
|Figure 5: Lemon grass grown using|
What Type of Fish can I Grow in an Aquaponics System?
Tilapia is the most common fish to be used in Aquaponics systems overseas, although the use of Tilapia in Australia is prohibited due to their ability to overtake and dominate local waterways. Barramundi, Silver Perch, Trout, Golden Perch, Catfish, Murray Cod, Jade Perch, Australian Bass, Black Bream, Eels and Yabbies are suited to the climate in Australia, and are legal to own and grow in Aquaponics systems in Australia. For more information on the types of fish allowed to be used in Australia in Aquaponics systems, contact the Department of Agriculture, Fisheries and Forestry or the relevant state department of Fisheries.
What do I Feed the Fish?
The type of fish that are being grown will determine the type of fish food that is used. There are fish foods that have been created to suit specific species of fish, and others that are more generalised. The type of food will also depend on the amount of production that is expected from the Aquaponics system. Food can also come in the form of live food including worms and snails. Fish feed is available for most species from pet shops and specialty aquarium shops.
A commercialised system will require the correct type and amounts to be given for the best production possible, whereas the backyard grower may not be as specific about the amount that needs to be grown for the system to be seen as successful.
How Many Fish am I Allowed to Have in each Tank?
Again this will depend on whether the system is a commercial or backyard system, with the commercial systems requiring the correct amount of fish and plants for optimum production. The more fish there are in a system, the more nutrients there are for the plants to consume, but if there are not enough plants to consume these nutrients, the excess build up in the water can cause the fish to suffer. As a general rule, backyard systems can stock between 10 - 30 kg of fish per 1000 litres of water.
What are the Main Components of an Aqaponics System?
- Fish tank
- Grow beds
- Water pump
- Aeration pump
- Mechanical Filtration
- Plumbing for irrigation and drainage
- For media based systems, medium is needed
- Fish and plants (seeds)
What Type of Fish Tank is Suitable?
Tanks used to house the fish can be made from any kind of water reservoir that is clean, and has preferably never held chemicals. This is especially important for plastic tanks, which can retain the chemical residue in its structure, and release it into the water slowly. This can lead to the fish becoming sick or even killed by the leaching poison. The cleaner the original setup of the system, the more likely you are to have a hassle free Aquaponics system for the long term.
Many backyard systems use bathtubs, inground ponds, barrels, spas and small rainwater tanks as the fish tank; your imagination is the only limiting factor in the design and choice of Aquaponics system components. When using a tank with a flat base, keep an eye on the build up of sludge at the bottom of the tank, and remove if needed. This build up can cause anaerobic areas to develop, which can cause an increase in ammonia levels and release toxins such as hydrogen sulphide into the water, which is toxic to fish.
Make sure that your tank is covered from direct sunlight by using a lid. Any direct light that gets into the tank will cause algae to grow, which takes away nutrients from the plants you are growing in the grow beds. Fish need just a little light so that they can see whether it is day or night, which keeps their natural rhythms in check.
How Deep Should my Grow Beds be in a Media Based system?
The standard depth of Aquaponic system grow beds are the same as those used in the hydroponic industry. The depths can vary from 10cm (100mm) to 30cm (300mm) with the deeper the bed, the more problems that can be encountered with cleaning out the roots of plants. The depth only needs to be as deep as the plants roots grow. These depths have enough area to harbor the bacteria needed to make an Aquaponics system stable and successful.
|Figure 6: Set up of aquaponic grower beds.||Figure 7: The growth of healthy plants in grower beds.|
What Type of Water Pump Should I Use?
Before you purchase a pump, you need to work out what size will suit the system. The water head is the highest point at which the pump needs to move water to. The higher this point the more energy is used. Most pumps will have a graph describing what they are rated to pump at certain water head. When designing and building the system, keep in mind that any pumping to a water head of unnecessary heights will mean you need a larger pump to cope with the extra pressure.
As well as water head pumping height, flow is restricted by friction losses. This is the friction of the water against the walls of the pipework as well as the restriction of any bends in the pipe. Friction losses can be minimised by using large pipes no longer than they need to be with as few bends as possible.
The operation of the pump also needs to be taken into account. Some pumps are designed for working constantly, while others are designed to be turned on and off many times a day. Some continuous pumps are not rated for stop-start operation, and their warranty is void if they are used in a stop-start manner. Check with your supplier beforehand to make sure the pump is suited to your application.
What Type of Air Pump Should I Use?
Much like water pumps, air pumps work harder and use more energy the deeper that the stone / diffuser is placed in the water. Purchasing a quality air pump, preferably with battery back up, ensures that the fish are always kept up to good levels with oxygen availability. Air pumps usually have performance graphs much like water pumps. Make sure that you will be getting the air flow that you desire at the depth you will be using the stones / diffusers.
What are the Different Bio-filtration Options?
Biofilters are a habitat for bacteria to live. Biofiltration is the term for 'processing of wastes by aerobic bacteria'. Biofilters are generally used to treat the fish tank water, especially in deep flow / raft systems and NFT systems. The biofilter usually contains biomedia, a plastic media which has been designed for maximum surface area to allow colonisation of bacteria, and is very light and easy to handle. The biofilter container is located between the fish tank and the grow beds, usually after simple mechanical filtration and is generally incorporated into the system so that no extra pumps are needed.
In a media based system, the medium (either gravel or expanded clay) acts as the biofilter, allowing bacteria to proliferate on its surface area.
What are the Different Mechanical Filtration Options?
Mechanical filtration is used to stop solids from entering the grow beds, especially used in deep flow / raft systems and NFT systems. When solids are allowed to enter grow beds, over time build up occurs and can cause anaerobic areas within the grow beds to develop, which in turn causes toxic substances to develop. The most basic form of mechanical filtration is to use a foam block underneath the irrigation pipe entering the grow beds. This is cleaned on a regular basis, and stops large amounts of sludge and uneaten food, it is a cheap and very easy way of creating mechanical filtration.
More professional methods of mechanical filtration involve using swirl separators / clarifiers, which take either all or part of the fish tank water, passing it through and collecting the solids. These solids are removed manually, and are a great fertiliser for soil based plants around the house.
How can I Make my System Safe for Children and Pets?
Cover the fish tank with a lockable lid, do not allow water to be accessible to children.
Be careful when working with water and electricity, the two don't mix.
Use low voltage power products that are not able to be accessed by children or pets. Cover power components and pumps froma rain and also protect then from the chance or water overflow from the fish tank.
How can I Make my System Energy Efficient?
- Low head design for both water and aeration systems.
- Use energy efficient water pumps and aerators.
- Design system with fish and plants that will not need to be heated or chilled.
- Pipework layout so that minimal friction losses occur.
- Locate system grow beds in sun for maximum production for plants, and fish tank in shade for regulation of water temperature.
Do I Need to Test my Water Regularly?
Regular testing is advised, generally every week to two weeks, especially in the first couple years until the system has become more balanced in itself. Normal recommended tests include ammonia, nitrite, nitrate, pH, iron and conductivity. These can all be done by you using test kits readily available online or through your aquarium supplier.
How Much Work is Required in Running an Aquaponics System?
Once up and running, the maintenance part of running a system kicks in. These duties include the following:
- Fish feeding
- Plant seeding and harvesting
- Mechanical filter clean
- Water testing
- Water top ups, unless autofill valve is connected
How do I Control Pests and Diseases in Plants?
Much like soil based plants, healthy plants repel pests and diseases. The best thing to do for your plants is run the system well, with enough nutrients to allow the plants to flourish. If problems with pests occur, no pesticides can be used, as they affect the health of the fish. Pest affected plants are normally removed from the system, and something else is planted in replacement. Much the same with diseases, the plants which are affected are removed and the source of the disease is tracked down. Many fungal infections occur due to lack of air circulation around the base of plants.
How do I Control Diseases in Fish?
The most common diseases in fish are bacterial infections, fungal infections and parasites. Aeration and water movement are critical for keeping fish healthy, as well as keeping the water clean and free from build up of solids. Different fish suffer from different diseases. Once you have decided which fish to stock, purchase a specialised book on the species, and find out as much as you can about its particular likes and dislikes.
Bacterial infections generally occur when stress or environmental change has happened. Many fish already have pathological organisms on or in their bodies, and it is not until they are under stress, which lowers their tolerances and their immune system, that the bacterial infection starts to become a problem. Early diagnosis allows you to change whatever is causing their stress before too many of the fish become sick or die. Prevention is the best cure, with adequate environmental conditions for the fish being the best way of keeping bacterial infections at bay.
Fungal infections on freshwater fish show up as white 'fluff' on their body and fins. Fungal infections generally occur if fish suffer physical damage or if the fish have already been weakened by another disease. Stress also weakens fish so that they are susceptible to getting fungal infections. Treatment of fungal infections is usually done by treating the water in which the fish are living, effectively treating the water and the fish at the same time. Any water that is being treated with a fungicide should not be pumped through the plant component of the Aquaponics system.
Parasites are difficult to detect without specialised techniques, and generally the parasites have no or little effect on the fish carrying the parasite. Many fish in the wild carry parasites, this is why it is not recommended to capture wild fish for relocation into a fish tank. Any fish with parasites will lower its resistance to the parasites in times of stress, causing a decline in health and vitality of the fish, and increased potential for other bacterial or fungal infections to appear.
This information is courtesy of Aquaponics Pty Ltd.