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Aquaponics is based on productive systems as they are found in nature. It can be loosely described as the combination of aquaculture and hydroponics and this is where the name aqua-ponics originates.
|Hydroponic systems rely heavily on the careful application of man-made nutrients for the optimum growth of plants. The nutrients are made from mixing together a concoction of chemicals, salts and trace elements to form the ‘perfect’ balance. Water in hydroponic systems needs to be discharged on periodically, as the salts and chemicals build up in the water which becomes toxic to the plants. Aquaculture systems focus on maximising growth of fish in tank or pond culture.|
The fish are usually heavily stocked in the tanks often, 10kg in 100L of water. The high stocking rates often mean that the tank water becomes polluted with fish effluent which gives off high concentrations of Ammonia. Water has to be discharged at a rate of 10-20% of the total volume in the tank once a day, everyday. This water is often pumped into open streams where it pollutes and destroys waterways.
Aquaponics combines both systems, and in doing so cancels out the negative aspects of each. Instead of adding toxic chemical solutions to grow plants, aquaponics uses highly nutritious fish effluent that contains almost all the required nutrients for optimum growth. Instead of discharging water, aquaponics uses the plants and the media in which they grow to clean and purify the water, after which it is returned to the fish tank. This water can be reused indefinitely and will only need to be replaced when it is lost through transpiration and evaporation.
Is Aquaponics Complicated?
It's as simple as it seems, pumping nutrient rich fish water past the roots of plants which extract the nutrient from the water. The principle method we deal with here is using grow beds filled with a medium, whether thats gravel, riverstone, crushed basalt, or expanded clay. Plants are grown in the media filled beds and water is pumped from a fish tank into the grow bed, draining through the gravel, and back into the fish tank.
Experimenting with aquaponics can be as simple or as complicated as you like, it could be as simple as an aquarium on a sunny windowsill with some goldfish, with water pumped into some gravel filled pots above it, draining through the gravel back into the aquarium. Once you have tried something simple you can progress up to a system with multiple grow beds and high stocking densities of fish.
There are three basic styles of aquaponic systems, which we discuss below in a little more detail.
Media filled beds
Media filled beds are the simplest form of aquaponics, they use containers filled with medium of expanded clay or similar. Water from a fish tank is pumped over the media filled beds, and plants grow in the rock media. This style of system can be run two different ways, with a continuous flow of water over the rocks, or by flooding and draining the grow bed, in a flood and drain or ebb and flow cycle.
NFT or Nutrient Film Technique
Nutrient Film Technique is a commonly used hydroponic method, but is not as common in aquaponic systems. In NFT systems, nutrient rich water is pumped down small enclosed gutters, the water flowing down the gutter is only a very thin film. Plants sit in small plastic cups allowing their roots to access the water and absorb the nutrients. NFT is only really suitable for certain types of plants, generally leafy green vegetables, larger plants will have root systems that are too big and invasive, or they become too heavy for the lightweight growing gutters.
DWC or Deep Water Culture
Deep Water Culture, works on the idea of floating plants on top of the water allowing the roots to hang down into the water. This can be done in a number of ways. This method is one of the more commonly practiced commercial methods. DWC can be done by floating a foam raft on top of the fish tank, however a more common method is to grow the fish in a fish tank and pump the water through a filtration system, and then into long channels where floating rafts filled with plants float on the water surface and extract the nutrients.
Which style is best for me?
So there are the basics of aquaponics, it really can be as simple or as complicated as you like, if you want to start off small and simple take a piece of polystyrene, cut some holes in it, stick some mint cuttings or water cress cuttings through the holes, and float it on the surface of an aquarium or pond, within no time you'll end up with a mass of floating herbs, and you'll have cleaner water for your fish. Through lots of experimenting over the years, and through the trials of members on the online discussion forum, the flood and drain media based system, has been found to be the most reliable and the simplest method of aquaponics, especially for beginners. It can be done very simply using a wide range of different containers. The flood and drain media bed system, also requires minimal maintenance.
The Nitrogen Cycle
One essential unseen element to an aquaponic system is the benefitial bacteria. The bacteria flourish in the dark moist gravel filled grow beds, and break down elements in the water into a form which the plants can absorb and use. An aquaponic system is organic due to it's very own nature. Synthetic fertilisers can't be fed to the plants or it will adversely affect the fish and the beneficial bacteria, the system has to be kept natural.
There are two different bacteria that break down wastes from the fish, the first is Nitrosomonas, which converts Ammonia into Nitrites. These Nitrites are then converted into Nitrates by Nitrobacter bacteria, the plants can then consume the nitrates to grow.
One interesting aspect of aquaponics is that it's a self balancing system to a great extent. As more nutrient becomes available through increased feeding of the fish, plant growth rates will increase to consume the extra nutrient. When fish are smaller or if the fish aren't being fed as much feed growth rates of the plants will slow down accordingly.
Recycled containers like IBC International Bulk Containers, as well as second hand plastic drums and other similar equipment are commonly used by people to build aquaponic systems. This is done for many reasons, recycled materials can generally be found around the home, or sourced from salvage outlets fairly cheap, so you can build quite a large system for very little initial cost. Just be careful when using second hand materials, it's useful to know what has been stored in containers before you decide to use them.
But really, there's no excuse not to give aquaponics a go, if you feel a little unsure about starting and you want to make sure you get the best head start, then you can look at starting off with a kit system.
If you're a handy person who prefers trying to build something from scratch, then keep your eyes peeled on refuge collections and at salvage retailers, bathtubs are ideal for aquaponic growbeds, and they have drain fittings preinstalled.
Many aquaponic styles are possible, it can be as simple as a pond with floating vegetation, through to incredibly complex systems with very high stocking densities of fish.
Here we discuss the different designs of aquaponic systems based on media filled grow beds. There are a few basic styles that have been adopted and trialled by many different people around the world, each of these styles has their own unique advantages and disadvantages associated with them.
Firstly there's two methods of applying water to the grow beds where the plants grow, firstly the continuous flow method, where water is pumped from the fish tank up to the surface of the grow bed. It then trickles down through the media and back into the fish tank. This is one of the simplest methods of aquaponics, however it does have a few disadvantages. The irrigated water tends to flow straight down through the media and then along the base of the grow bed to the outlet, without depositing all of the nutrients into the grow bed. To counter this a grid of irrigation pipes arcoss the surface of the grow bed should be used, so that more of the media gets wet and plant roots can make the most of the water and nutrients. If there is no irrigation grid them most of the media will remain dry and will neither function as a biofilter or growing area for plants.
One of the means of overcoming this problem is to have the outlet back to the fish tank at a higher point and to keep the grow bed permanently flooded to a certain level. This improves the situation but it's still not ideal, plant roots can become waterlogged, areas of the grow bed can become stagnant and anaerobic, as the flow of fresh water through the bed moves around any blockages. Ideal the media filled grow beds should be moist 90% of the time to take advantage of greater biofilter properties, which enables a stronger bacteria colony, as well as greater growing area for plants, while also keeping as much of the media filled bed flowing as freely as possible without any blockages.
Flood and Drain (Ebb and Flow)
By mimicking the natural cycle similar to waves or tidal surges, we can gain the benefits of having the media filled beds flood and drain completely, allowing oxygen into the root zones of the plants, while also limiting the build up of solids within the grow bed, because of the constant surging action of the water as it floods and drains within the media beds. With the beds flooding regularly, it has more potential for plant growth throughout the entire bed, while reducing the requirement for extensive irrigation grids across the surface of the grow bed.
During trials of numerous systems by many enthusiasts, including various people across the world it has been found that, the advantages of flood and drain aquaponic systems, outweigh any advantages of a continuous flow system. This doesn't mean that continuous flow systems don't work. Joel Malcolms oldest system is a continuous flow system, at the time of doing this website the system is about 7-8 years old and still working very well.
Constant Height In Fish Tank - Pump In Sump Tank
This style of system uses a pump in the sump tank that pumps water into the fish tank, the overflow pipe causes the water to flow out of the fish tank, when it exceeds a certain height, and into a grow bed where it drains back into the sump tank. A simple version of this system can be seen on the left, the black pipe pumps water into the fish tank, while water flows out of the white PVC pipe into the the grow bed before draining back into the sump. This system was run with a timer on the pump and a restricted outlet on the drain, this allowed for a flooding and draining action in the grow bed.
CHIFT PIST systems have many advantages over other methods, and they have a few disadvantages. The main advantage of a CHIFT PIST system, is that it means there is no pump in the fish tank, the fish tank stays at a fairly constant height, and if there's ever a pump failure or blackout the fish tank will stay full. Disadvantages are that you need a sump tank with a large volume and a short height, to hold the water and you also need a tall or raised fish tank.
Simple Flood and Drain
This is possibly the most simple method of setting up a flood and drain system. The grow bed sits above the fish tank, water is pumped from the fish tank into the grow bed, then the water drains straight back into the fish tank below. The ultimate in simplicity. If there's a problem with the pump or power supply the water drains straight back into the fish tank. This style of system is compact and has very few disadvantages, the only minor disadvantage is that the water level in the fish tank fluctuates when flooding the beds. Also the pump is in the fish tank so if it's only a small pump with limited solid pumping capacity, solid wastes may clog up the pump, requiring periodic maintenance.
Sump Tank Two Pump
A two pump sump tank system works by pumping water from the fish tank into the grow beds, the water then drains from the grow beds into a sump tank. Within the sump tank is a pump operated by a float valve, as the water level in the sump tank rises the pump switches on, pumping water back into the main fish tank. The float valve switches the pump within the sump tank on and off, the hieght that it turns on can be set so that the sump tank retains a good volume of water, allowing a second species of fish, or young fingerlings to be stocked in the sump tank.There are some disadvantages and advantages of having a sump tank incorporated in an aquaponic system. Generally having a sump tank means that water is pumped back numerous times per hour to the fish tank supplying freshly oxygenated water to the fish. It allows quite a large system to be built without having to dig or bury any tanks into the ground, and it allows for the
|stocking of fingerlings or other species within the sump tank. The disadvantages of this system is that it requires two pumps and, if there's a power failure, and the grow beds all happen to be full then there's a chance that the sump tank may overflow, losing water from the system.|
There are a few of simple ways to flood and drain an aquaponic system, firstly a timer can be used to regulate the pump that's filling the grow beds . A simple way to do this is by using stand pipes, stand pipes set the maximum water level in a grow bed, and excess water that is pumped into the bed goes straight over the top of the stand pipe and down the drain. When the pump turns off water drains slowly from the bed through small holes in the base of the standpipe.
Another method of creating a flood and drain cycle within a grow bed, is by using an 'autosiphon'. Autosiphons rely on a constant, relatively slow flow of water, into the grow bed. When the grow bed water level gets to a certain height it prompts the autosiphon to drain the bed, because of the change in pressure around the autosiphon. This drains the bed quickly of the water. Autosiphons can be a little fiddly and can be prone to failures on occasion but they are fun to experiment with.
Really there's no end to the different ways that you can design an aquaponic system, it's best to begin with a simple system, so that you can get a feel for aquaponics and how it works, before trying more complex methods. Flood and drain methods definitely hold more advantages than continuous flow methods, and the stand pipe / timer method is the most simple to start with as nothing major can go wrong.
Importance of fish
Fish are the power house of an aquaponics system, they provide the nutrients for the plants and if your growing edible fish, then they also provide protein for yourself. Keeping fish may be a little daunting to some, especially those without any prior experience, however you shouldn't be discouraged. Keeping fish in an aquaponic system is more simple than keeping aquarium fish, so long as you follow simple guidelines then growing fish from fingerling size, to ready to eat fish can be extremely simple.
Choosing a fish species
There are many different species of fish that can be used in an aquaponic system, depending on your local climates and available supplies. There are also a few choices for year round fish that we could grow, but they often take a longer time to mature. If you live in a cooler climate you might be looking at growing Trout all year round, or perhaps another locally produced fish species. In warmer areas people generally grow Barramundi, or Jade Perch year round, in most warm areas throughout the world Tilapia is the fish of choice.
In deciding what is the best species for you to grow, you should take a few factors into account, most importantly is what you want from your system. If you don't want to eat your fish then you probably won't want to grow edible fish, or you may want to grow an edible fish that can live year-round in your area, so that you're not having to harvest fish out seasonally. The second most important factor is 'What's available?' You need to be able to buy fish to stock your system, even with species such as Tilapia that breed readily, you need to get your broodstock in the first place.
Here's a list of useful aquaponic species with a few details about each
Barramundi are often grown in aquaponic systems through the warmer months of the year. Most growers will buy fairly mature stock so that they can harvest larger fish, at the end of the growing season. Barramundi that is grown in an aquaponic system has an exceptionally clean, crisp taste. Growing your own Barramundi excites guests and is the envy of neighbours. They provide a decent harvest at the end of the season and are one of the more majestic species of edible fish.
There are many different species of catfish around the world that are well suited to aquaponics. Channel catfish are the most widely farmed aquaculture species in the United States, and they are available in many areas of Australia. Catfish don't have scales so they need to be skinned, they are quick growing and have a good food conversion ratio.
There are many species of carp that could be very well suited to aquaponics, unfortunately because of their reproductive capabilities, their tough nature and ability to readily adapt in many areas of the world, carp have become noxious pests to native waterways and the environment, and as such they are not easily obtainable, and often there are high fines and fees for keeping them. In most western cultures carp also have a fairly poor reputation, as an eating fish, however, carp is still the most widely cultured fish in the world as it's grown throughout most of Asia.
Although some people may group these with the carp, I've decided to cover these seperately as most people refer to them as goldfish, and this is what they will be sold as, at local pet shops or fish suppliers. Goldfish are generally pretty tough and make a great addition to an aquaponic system. In many areas they will breed in a tank, although they generally need plant cover within the tank to breed.
This native Australian fish i's worth a special mention here, as it has the highest levels of omega three oils of any fish species in the world. In fact it's so high in omega three oils that growers are trying to breed the oil out of them, they are trying to breed a less oily fish because they've found people don't like the high oil content.
They require warm water and consume an omnivorous diet. Very well suited to an aquaponic system, they grow quickly and fingerlings are readily available in warmer areas.
Once again, another species of carp, but better known as "Koi" rather than carp. Koi are very common within many Asian communities and they are often found in large ornamental ponds. For those who love Koi, an aquaponic system is a great proposition for stocking the fish.
Murray cod are a magnificent native Australian fish, known to grow to enormous sizes in their native habitats, their tank culture is still in reasonably early days. Murray cod are grown in recirculating aquaculture systems, and can also been grown in aquaponic systems, hopefully this fish will be utilised more over time because they are quick growing, and a great eating fish. One of the downfalls is that they must be kept at high stocking densities, and kept well fed otherwise they cannibalise each other.
Silver perch are a good allround native Australian fish that grow well under a variety of conditions. Perch are omnivorous and will happily eat green scraps as well as Duckweed and Azolla. They grow within a wide temperature range, though they're not as fast growing as many other fish, taking 12-18 months for fingerlings to grow to plate size.
TilapiaThe second most cultured fish in the world, and extremely popular in Aquaponics systems. They are an ideal species for aquaponics for many reasons. They are easy to breed, fast growing, withstand very poor water conditions, consume an omnivorous diet and are good eating. The only downfall for some people will be that Tilapia require warm water. If you live in a cool area you are far better off growing a fish species that will grow well in your temperature range, rather than trying to heat the water. Tilapia are also a declared pest in many areas.
Trout are a great fish for aquaponic systems where water temperatures are a little cooler. Trout prefer water temperatures between 10°C and 20°C. They have extremely fast growth rates and excellent food conversion ratios.
There are other fish species which are quite suitable for aquaponics, that might be available in your local area. In Europe many different species of carp are grown, within the United States such species as Bluegill are often available, while in Australia we also have a number of other native species like Sleepy cod which would be suitable.
Other aquatic animals that can be incorporated into an aquaponic system are fresh water mussles, fresh water prawns, and fresh water crayfish. Mussles are a filter-feeder, and do a great job of helping to clean the water, they will happily grow in flooded grow beds, or can be incorporated into fish tanks. Crustaceans make a nice addition to an aquaponic system and there are a few different species available depending on your location and water temperatures.
For those in tropical areas there's Redclaw, a fast growing native Australian species, and for those in cooler areas there's Yabbies or Marron.
Yabbies breed readily, given the right environment and the correct water temperature, as well as long daylight hours. They also grow fairly quickly, but they can be prone to fighting and cannibalism when stocked very densely. The Yabby is also a attractive crustacean as seen from this picture to the left.
Numbers of Fish
This can be quite a hot topic of debate amongst people who practice aquaponics. Stocking levels of fish within a system can be as high as many intensive recirculating aquaculture systems, however the higher the stocking density the higher the likelihood of things going wrong. In very heavy stocking densities you need to keep a constant eye on all water parameters to be sure that conditions are kept at the optimum.
If you lower the stocking levels of fish then you lower your levels of risk and stress. Growth rates of plants in lightly stocked systems can still be very impressive, this eight bed system was stocked with only 70 fish, thats less than 9 fish per growbed. The fish tank is 5000L and there's a 1000L sump on the system. The fish in the system at the time of taking this photo were trout and they were around 300 - 400g. The plant growth in the eight beds was fantastic. A wide mixture of plants were grown in the beds.
We are often asked which plants grow well in an aquaponics system and it seems that most herbs and vegetables adapt well to aquaponics. Of course some plants won't do as well when using different methods, media filled beds seem to be the most successful for growing a large range of plants, and you can grow just about anything.
We often hear people say "But isn't aquaponics only good for leafy green plants?" This is a fallacy that has perpetuated for quite some time, but as you will see from the list at the bottom of this page, aquaponics will grow just about anything. This Habanero chilli plant on the right grew a fantastic crop of super hot chillies, and a single tomato plant in a nearby grow bed produced well over 30 kg of tomatoes. Some other fruiting varieties that perform well are; eggplant (aubergine), capsicum (bell peper), bean, peas and many more.
What about root crops? No problem, although you are probably better off growing potatoes in the ground, they will still grow successfully in an aquaponic grow bed. Carrots are another great root crop in media beds, carrots harvested from grow beds have no sand on them and although you might wonder, how they grow in a bed filled with gravel they do a surprisingly good job.
Beetroot are another winner, we grow a lot of fresh beetroot and they grow to a fantastic size if you let them go for long enough, the beetroot on the left was over 1kg.
What about deficiencies?
Just as with all gardening you may get some deficiencies in your plants, but generally this can be dealt with very simply. Seaweed extracts are a great way to supplement almost all minerals that might be lacking in an aquaponic system, seaweed extracts come in many different forms, and consideration towards harmful additives needs to be paramount as anything you add in the system will be passed on to both fish, bacteria, plants and you. You can also use powdered mineral substances. There are a number of different ones on the market, but once again, you must take care in their application if you haven't used them before, remember, it's not just the plants your caring for but also the fish and the bacteria population. The best way to stay on top of deficiencies, is to use a good quality aquaculture feed for your fish. Most good quality feeds have a percentage of ocean caught bi-product, this means that there's a good range of minerals and trace elements within the fish feed. We have some systems that have not had any supplemental addition of minerals, for well over 12 months and plant growth is exceptional.
Can I plant seeds?
Definitely. In media filled beds we generally use a combination of seedlings and seeds. When first planting a grow bed in a new system, we recommend sprinkling a mixture of seeds over the grow bed, as well as planting seedlings in the bed. Planting seedlings is simple, we recommend that you use normal seedlings, but before you plant the seedlings, wash off the majority of the potting mix from the root ball in a small bucket of water, the potting mix should wash off fairly easily with just a gentle shake in the water.
While planting out the seedlings in the beds the media agitation causes the seeds that were sprinkled over the bed before, to fall down in between the media where it can absorb water and safely germinate. During planting trials I've found that this method has many benefits. As the seedlings grow and shelter the germinating seeds they tend to dominate the beds, and many of the germinating seeds can only grow very slowly, however, once the planted seedling matures and gets harvested, this opens up the canopy giving the small plants that germinated from seed a chance to take off. These plants now have a mature root system, and a great head start so they can grow very quickly. This mimics natural forest ecosystems, where young trees and other undergrowth grow quite slowly, until a large tree dies and the canopy opens up allowing light to get to the lower plants, which then stimulates their growth.
What are growth rates like?
Growth rates of plants in aquaponic systems can be quite phenomenal, in fact a trial by Dr Nick Savidov in Canada, found that aquaponic growth rates can exceed hydroponic plant growth by up to four times with some vegetables and herbs. The advantage of aquaponics over soil grown vegetables is that, during warm weather the plants get as much water as they need, due to the regular flooding of grow beds in an aquaponic system. Plants grown in the ground can use the water around their root system, very quickly in hot weather, leading to wilting from a lack of water very quickly, on a hot day. Plants in an aquaponic system get watered constantly, so they always have water, no matter how hot the weather is.
Here are some young plants in a grow bed, Joel Malcolm photographed these everyday to keep a record of the growth rates of the plants. The bed was planted with different varieties of basil, mizuna, cucumber and broccoli
13 days after the first photograph, all of the plants are growing quite well
25 days from the first picture. Joel has already harvested a couple of cucumbers and there are many more to come, with plenty of fresh herbs and salad greens also available.
Joel has grown chives that were over one metre in length in the same system as you see above..
This is a list of plants that grew well for members of the, this is by no means an exhaustive list of all plants that will grow well, just a few of the great performers that forum members have grown.
Simpson's Curled (Lettuce)
Oregon Sugar Pod (Peas)
Bloomsdale Savoy (Spinach)
White Bunching (Onion)
Tomato (Grosse Lisse)
Silver Beet (Giant Fordhook)
Lettuce (All seasons)
Basil (Sweet green, purple, curly leaf and Thai)
Parsley (Flat leaf and curly leaf)
Numerous tomato varieties (the only tomato variety that hasn't grown well was pineapple)
Yugoslavian watercress (also known as Lebanese watercress or Bulgarian watercress)
Chives (normal and garlic variety)
Chillies, many varieties, haven't found a variety that hasn't grown well yet
Kohl Rabi (Purple vienna)
Egg plant (Black beauty)
Capsicum (Californian wonder, Yolo wonder, Long sweet yellow)
Cucumber (Burpless, Armenian)
Dwarf beans (Butter beans)
Of course the plants you grow in your system may be limited by the type of aquaponics system you have, or more to the point, the type of plant growing system. If you have an NFT system you will not be growing carrots or large tomato plants because the small NFT pipes will not allow such growth. If designing your own aquaponic system you must put some thought into your plant growing method, and what you want to grow. This is one of the reason why we like deep media filled beds at Farm Tech Mart, when you have deep media beds there are no limitations on growing different plants.
Malaysia Farm Supply, Agriculture Technology,
Hydroponic, Aquaponic, Organic Farming, Plantation
Solar Panel, Electric Fence, Wind Power, Ventilation Fan, Pump, Irrigation, Fish Farming, Fisherman Equipement
ph: 603-8052-0078 (Sales)
fax: 603-5882-1962 (Fax)
alt: 603-5882-9110 (Corporate)