Fish Food – How Much Do I Give Them Per Feed.

Fish Food—Feeding your fish using commercially available sinking or floating pellets. The fish food we supply is suitable for all Australian Natives. The fish food has NO land animal content.  This is a very important consideration. Land animal content is … Continue reading

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Plants With Wet Feet.

Aquaponics Ripe pawpaws on tree

An Aquaponics Papaya or Pawpaw tree heavily laden with fruit.

Plants with wet feet

I want to be able to grow fruit trees as well vegetables.  As you can see, I am having wonderful success with the Paw Paw (papaya) trees.

Aquaponics pawpaw.

Look at these beauties. Yes…grown in Aquaponics media beds 300mm (1′) deep.

I’ve got a good friend who is a retired Paw Paw (papaya) grower from way up in North Queensland and he came and told me that we simply could not grow Paw Paws (papaya) in this environment because, evidently, Paw Paws (papaya) don’t like wet feet.

Have you heard that expression, “you can’t grow that plant in those conditions as it doesn’t like wet feet”?

It would be more correct to say that the plant does not like lack of oxygen around its roots!

If we are running a flood and drain system, where we flood the bed and then drain the bed, we flood the bed, we drain the bed, over and over, continuously.

What we are actually doing is delivering water and nutrients every time we flood the bed, and loads of fresh oxygen is being delivered every time we  drain the bed.  The plants that just should not grow in a very moist environment actually grow extremely well, why?  Because they are getting all the nutrients that they want, all the water they want, and they are actually getting all the oxygen they want around their roots.  That’s how we have been able to grow Paw Paws (papaya) so successfully.


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Aquaponics System Biology…1

SCOPE: To discover the important parameters and better understand the role of natural processes in an Aquaponic System.

Aquaponics System Biology…1

We understand that in Aquaponics system produces fish and plants together in one symbiotic system, and we now know that there are two major bacteria that convert the primary waste of the fish, Ammonia to Nitrates, that is, plant food.

Just to recap on those two Bacteria families are …
1. Nitrosomonas bacteria
2. Nitrobacter bacteria
Bacteria of various types is all around us and in our own bodies. There are simply millions of different bacteria. In nature bacteria perform many complex tasks taking one compound and by extracting energy from it for themselves convert it to another compound. These two bacteria groups listed above are particularly important to our needs and given the right conditions will work for us around the clock.

Bacteria needs a food source, water, and be housed within a temperature and pH range conducive to their happy survival.


  • The temperature for optimum growth of nitrifying bacteria is between 77-86° F (25-30°C).
  • Growth rate is decreased by 50% at 64° F (18° C).
  • Growth rate is decreased by 75% at 46-50° F. (8 to 10 C)
  • No activity will occur at 39° F (4° C)
  • Nitrifying bacteria will die at 32° F (0° C).
  • Nitrifying bacteria will die at 120° F (49° C)  (1)

Nitrobacter bacteria is less tolerant of low temperatures than Nitrosomonas bacteria. In Aquaponics systems, care must be taken to monitor the accumulation of nitrites especially when there is a change in water temperature of the system.

pH range.

  • The optimum pH range for Nitrosomonas is between 7.8-8.0.
  • The optimum pH range for Nitrobacter is between 7.3-7.5

Nitrobacter will grow more slowly at the high pH levels . At high pH Nitrosomonas will grow more slowly and increases in ammonia may become evident. On the low end Nitrosomonas growth is inhibited at a pH of 6.5. All nitrification is inhibited if the pH drops to 6.0 or less.

Care must be taken to monitor ammonia if the pH begins to drop close to 6.5 as it may not be being processed as quickly as it is at higher pH levels.
This information has been taken from standard texts on the subject and we have observed that the tolerance range is most likely wider than most texts suggest. (2)

Beneficial Bacteria have four main benefits for areas like fish intestine lining and plant root tissue.

  • Beneficial bacteria help the balance of a system by: (Fungi help as well but that is another discussion)
  • Preventing harmful bacteria from taking hold. If the system is already occupied by a beneficial bacteria then the harmful bacteria has difficulty in taking hold. The microbes make Aquaculture and Aquaponics possible.
  • Promoting system health. Beneficial bacteria play an integral part in breakdown of organic material and actively assist plant and fish tissue health.
  • Being antagonistic to harmful bacteria. Beneficial bacteria inhibit harmful bacteria taking hold. By actively antagonising harmful bacteria the harmful bacteria are held in check in the Aquaponics system.
  • Improving nutrient uptake and general system health.

Aquaponics Microbes:-
It is most important to understand that many more things other than just the two bacteria groups discussed above. Many more are at work in the natural ECO system that we have pulled together in building an Aquaponics system. Fungi, algae, zooplankton, phytoplankton, protozoa, nematodes, just to list some. All of these microbes are the “work horses” of the system. Bacteria process the fish wastes into products that are non-toxic to the fish and make these products available to the plants as food.

Learn more about the actual numbers and parameters by attending the Practical Aquaponics Master Class

(1) Nitrifying Bacteria Facts – Bio-Con Labs. (n.d.).
Retrieved from

(2) Bhaskar Vijaya , E?ect of environmental factors on nitrifying bacteria isolated from the rhizosphere of Setaria italica : Department of Microbiology, Sri Krishnadevaraya University, Anantapur 515003, AP, India. 2005.


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Jade Perch, Tilapia and Lettuce…Common Requirements.

Keeping fish and plants together has some basic requirements and important parameters.

Digital thermometer in an Aquaponics system used to switch electric heaters on and off in a 2 degree range. Temp shown is centigrade.

Digital thermometer in an Aquaponics system used to switch electric heaters on and off in a 2 degree range. Temp shown is centigrade.

Water temperature is a very important parameter. If the water temperature gets too high it will knock the plant performance back. The ideal temp for both plants, Jade Perch and Tilapia is 23C ( 73F) as it goes higher or lower the performance of both plants and fish drops off.  Tilapia will still be fine in water up to 30C (86F) and a little way beyond.  Plants will also survive but do much less well, particularly lettuce and the like.

The system water temps do not necessarily follow exactly the outside air temp although they will gradually trend upwards in a succession of hot days. We see weeks of 33 -35C (90 – 95F) here in our South Queensland summer, our nights are usually average around 21C (70F) so over the summer the water temp gradually climbs to level out around 28 – 30C (83 – 86F) Not so bad. Everything works just fine in that temperature range.

The system water in our Aquaponics garden is the nutrient and dissolved oxygen transport vehicle as well as providing moisture for the plants and fish.  In a well designed Aquaponics garden nutrient and dissolved oxygen are continuously moved around and made available throughout the Aquaponics system.  Obviously both plants and fish will do much better when both dissolved oxygen and temperature are at or close to ideal levels.

This last summer we had one week of temps above 40C (104F) with one Saturday to 46C (115F) which was just an unbelievable day.

Hot mate, you could fry an egg on the footpath!

Fried egg.

That day my water temps got to 34C ( 95F) and I lost a number of fish. All big guys too which was very upsetting. I was away for the day so could not do anything about it till I got home just before dark to find fish gasping at the surface and a number of dead fish.

Above 30C (86F) the ability of the water to hold dissolved oxygen drops off rapidly so, result equals fish deaths and plant destruction. Water will only hold half the saturation of oxygen at 30C (86F) that can be held at 0C (32F).

Interestingly, if you can maintain reasonable root zone temps the plants may wilt a bit during a very hot day but will recover rapidly once the evening comes and will still grow and bear fruit in the case of tomatoes and cucumber for example.

So….root zone temperature control is the holy grail of delivering excellent results in your Aquaponics system.

Temperature control is equally important in cold climates, winter conditions.  Depending on where you are in the world this can be challenging or not so bad.   We will deal with that in another post.

I hope this is helpful to you.


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Grow Bed Area Needed To Achieve Crop Yields.

The area needed is arbitary because it depends very much on how well you manage your Aquaponics garden, the types of crop grown and so on. Also efficency improves as the garden gets bigger. What crop to grow, how many to plant, when, how often? Your local climatic conditions play a major part in the equasion. Serious planning and attention is required to make it happen.

It is generally accepted , by working a regular dirt garden you will need 30 sqm (320 sqf) to feed a typical family of 4. That will then be 7.5 sqm (80 sqf) per person. I believe that an Aquaponic garden is much more efficent than a regular garden so the growing area required will be less.

We have spent a long time thinking about this question and observing what we can and have achieved over the last 8 years and we believe 23 sqm (250 sqf) of AP gardening space is needed to feed a family of 4…..with all the skill and attention needed to make the garden sing. So, that is approx 6 sqm (62 sqf) per person.

Aquaponics is still a garden, and successful gardening requires time and dedication. 

Aquaponics INDY 23 fish garden.

Indy 23 Fish Garden.

This INDY 23 plan set is the result of 8 years of practical AP, full time 7 days a week. 23 sqm (250 sqf) of growing area spread over three different growing methodologies to produce a wide variety of produce and a realistic number of fish dinners.

If you want to be serious about food production for your family this is the minimum required…..sorry.  And if you seriously do want to produce a really big chunk of your family food needs, a few other things like a half dozen egg laying chickens, some space for fruit trees and so on will need to be added to the project. Let’s take a realistic approach to home grown, chemical free, nutrient dense food.

But, to move toward this goal step by step, and to produce what you can, to aquire the skills needed takes time and effort. Start to produce what you can in the time and space you have available to you. The INDY 11.5 is an excellent smaller system for this purpose. 

Take the time to aquire good sound knowledge. Frankly, watching a dozen or so You Tube clips made by people who started Aquaponics a few weeks before probibly won’t cut it…sorry.  Buy a book or a DVD from a good reliable experienced source. Trouble is we see on the internet people making crazy claims, no doubt we have all seen them, “10 times the vegetables, in half the time, twice as big.” 2000 lbs of vegetables from a kit made out of a couple of old IBC’s, a few bits of pipe all held together with string…..;) 

The “amchair generals”….:frustrated:

The magic about Aquaponics is,
#1 Aquaponics is an ECO system and the veggies and fish produced are clean nutritionally rich family food. Much, much better than “Organic”.
#2 It is more efficient than a regular garden because the plants have delivered to them water and nutrients continuously 24/7. The fish grow up in a healthy protected environment.

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C.H.O.P Aquaponics Operating System.

CHOP System.

The CHOP system is an acronym for   “Constant Height One Pump”. This is the most efficient way to run an Aquaponics system.

The basic principal is to use the force of gravity to assist us where possible. This brings high efficiency in electric power consumption and plumbing design.

The CHOP system is also better for the health and wellbeing of the fish, as it means there is more water in circulation that brings stability in both temperature and pH.  Because the fish tank is always full of water, the fish are safe if something goes wrong with plumbing or pump.  The auto siphon system is an automatic way to flood and drain the media beds without the need to employ float switches or timers.  The system is lower maintenance than older system designs that required float switches, timers and a second pump.

CHOP or Constant Height One Pump has been adopted by Aquaponics enthusiasts around the world and its popularity has demonstrated the methodology’s effectiveness.  The other variant CHIFT PIST (Constant Height In Fish Tank. Pump In Sump Tank) runs in a similar way.  In fact CHOP as an acronym was coined because the acronym CHIFT PIST was thought to be a little clumsy and crude.

Constant height in the fish tank is important in that we want to have a system design that ensure that the fish tank cannot be run or pumped dry should something go wrong, such as a pipe failure somewhere in the system.  If something goes wrong and the sump is pumped dry and or the media beds run dry, it is not desirable but it is not a disaster as would be the case if the fish tank is pumped or drained dry.

One pump is important from an economical operation point of view. So, our plumbing design is such that all the water can be moved around to all parts, in the volumes we require for each section of the system, by the one pump.

The pump resides in the sump. All pumping is done from here. I like to call the sump “Grand Central Station”. It is the central meeting point of all the water flow in the system. The water is pumped from the sump to the fish tank, and from the fish tank the water runs by gravity to the media beds.  The auto siphon or timer allows the bed to fill then drain back down to the sump.   In this way there is only one regulated flow around the entire system and that flow rate is dictated by the auto siphon/s.

CHOP system methodology allows us to use the absolute minimum of power to move the water around.  Aquaponics systems are perfectly natural systems except we have to move the water, and we can only do that with pumps of some sort or another.  So, over a period of time we have strived to get our pump size down and enjoy a very minimum of power usage.  In CHOP systems the water flow in one direction is done by gravity and in the other direction it is removed from the sumps back to the fish tank by the most efficient pump possible.

Originally, our systems had two pumps in them all the time, one was required to move the water out from the fish tank and one to move it back and we quickly discovered that that was just a waste of energy. This is another advantage of the CHOP system.

CHOP 2 System.

Chop #2 is a further and much improved variant to the standard CHOP methodology.  We noticed a problem with water levels whilst working on a small commercial CHOP system we were commissioning.  Running the feed water from the fish tank via a filter then on to be distributed to each media bed by gravity flow was problematic.  If all the beds were not precisely level with each other the lower bed/s would receive more water than the others. This could be regulated with valves on each bed water inlet.  This works fine on small systems, but the larger the system the larger the pipe work needs to be in order to accommodate sufficient water flow by gravity. Evenly distributing water by gravity to six beds that together were 30 meters (98’) long was near impossible.

We needed to refine the process for our client, so we came up with a solution that has been working well for several years, and now on many thousands of home systems and a good number of commercial systems. Pumping the water to the media beds, positive pressure delivery instead of gravity delivery.  It is relatively easy to ensure even distribution to each bed and also to the most distant bed delivering the water by positive pumped, or header tank pressure. The system water is delivered to all points under pressure, either by pump or from a header tank. The pump is located in the common collection and distribution point; the sump.  All the water arrives from the various parts of the Aquaponics system into the sump, all water leaves from the sump to the various parts of the Aquaponics system.

Water is delivered, as necessary, in various loops to the media beds, the raft beds, the fish tank and if included, to the mechanical filter.  The water is collected from each loop or system segment back to the sump.  The water is delivered to each loop or system segment from the sump under pressure either by pump or header tank.  The water flow is regulated to each part of the overall system by the use of a simple valve or tap.  Very accurate flows can therefore be achieved.  CHOP 2 allows the operation of each element of our Aquaponics system at its ideal flow rate. This multi loop arrangement allows much more flexibility in plumbing design and precise flow control through the various elements of the overall Aquaponics system.

Happy Aquaponics.



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It’s Like The African Jungle – Indy 23

Prue and Andrew decided to build an Indy 23 Aquaponics system after completing one of our 4 day Aquaponics Future Farm courses.

Well, without too much text we will show the photos.  These were taken just two months after the system was planted out.

The system is cycled although there are still some lingering pH issues that will settle down soon.

Seasol seaweed extract.

Seasol seaweed extract.

The system is regularly dosed with Seasol seaweed extract as per what we recommend for new systems.

The growth is remarkable from a new system that has 100 Jade Perch fingerlings and 25 x 1 year old Jade Perch in the second fish tank.

Beneficial bacteria are establishing their presence in the system processing the ammonia from the fish waste. This together with the action of the Seasol, myriads of microbes are at work building up a wonderful nutrient base that is in turn delivering excellent plants for food.

Indy 23 system builds are currently underway in Australia, USA, Spain, Cyprus, South Africa, Singapore, Indonesia, Israel, Philippines, Namibia, Thailand, Great Britain, Hong Kong, Malaysia and Austria.

So as the photos that follow testify…the shocking truth is that the INDY 23 Aquaponics system produces extraordinarily well.

Large healthy plant leaves.

Large healthy plant leaves.


Cucumber and Climbing Beans Aquaponics Indy 23 system

Cucumber and Climbing Beans






Climbing plants.

Climbing plants.

Zucchini in flower

Zucchini in flower









passion fruit

Passion fruit.


Lettuce. Many varieties.










More details about the Indy 23 Plan set can be found here.

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Aquaponics Water Supply – Municipal or Town Water – Tech Tip.

Top up water for your Aquaponics system can come from several sources.

In this Tech Tip we will discuss Town or Municipal water.

Aquaponics water tower Aquaponics

Municipal Water Supply contains all sorts of chemicals.

Town or Municipal water should not need testing. Chemical analysis of your local municipal water is usually obtainable from your municipal water supply authority.  A phone call to your water authority will often be enough for you to discover the important parameters.

Municipal water will contain chlorine or chloramine. These are added to kill bacteria and other living organisms, including fish, that may be present in the water supply.

Chlorine is easily gassed off by putting it into a holding tank, applying vigorous aeration for 24 hours.

Chloramine (NH2Cl) is commonly used in municipal water as an alternative to chlorine.  Chloramine is much more stable and does not dissipate as rapidly as free chlorine. Chloramine is formed by ammonia and chlorine being combined. Some chloramines could readily form in Aquaponics system water if you were to add chlorinated water straight from the tap to an Aquaponics system tank that already carried some free ammonia. If you cannot get a report from your water authority and you strongly suspect the presence of chloramines, obtain a test kit that is able to test for “total chlorine” or “combined chlorine,” not for “free chlorine.” A test for “free chlorine” would misleadingly read zero in chloraminated water.  ( 2014)

Chloramines can be removed from your source water by,

  • Boiling and degassing. (not very practical for large quantities)
  • Ultraviolet light. (Well established method of removal). (Adelstein, B 2013)
  • Activated carbon filter. (pass the water through slowly)
  • Commercially available de-chloramination products (some simply remove the chlorine, while others ‘lock up’ or detoxify remaining ammonia) ( 2014)

It is best to treat any suspect water in a holding tank before using for top up in the Aquaponics system proper.

More Teck Tips on water supply in following blogs.

See our training courses Here

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Fish Problems & Diseases.

Fish Problems & Diseases.

Our Aquaponics fish can be subjected to various difficulties that will cause them to be in a less-than-ideal situation leading to sickness and death. Most fish problems are human induced.

There are not that many diseases your Aquaponics fish can contract.  If you buy your fingerlings from a hatchery that can issue a health certificate for the fish, then buy from that hatchery.  It is well worth the little extra it may cost to buy fingerlings from a certified source. That way you start off well and provided you have good water quality and loads of aeration, there is a very good chance that your fish will not get sick.

Stress.  Fish can easily become stresses by a number of factors. Do everything to keep your fish happy and feeling safe.  Stress is detrimental to fish health just as it is for humans and any other animal. Prolonged stress sets the fish up for bad health outcomes.
Stress is identified by,

  • Fish are skittish and easily disturbed.
  • Gasping at the surface.
  • Strange swimming patterns.
  • Loss of interest in feeding.

Stress can be caused by,

  • Poor water quality, pH , excessive nitrate, nitrite, ammonia.
  • Excess of dissolved solids.
  • Low dissolved oxygen. Power outages. Pump failure.
  • Bullying by other fish.
  • Excessive handling by humans.
  • ICH. Sometimes named “white spot”. The  scientific name isIchthyophthirius multifilis.   

Treat and avoid stress by,

  • Cleaning up the water quality in your system. This may require the cleaning of the filter if you have one fitted to your system.
  • Fit a filter, a simple settlement tank or swirl filter will make a world of difference if the system has visible solids in the water column.
  • Feed at the correct rate. Overfeeding brings on a raft of difficulties.
  • Ensure the system is within parameters for pH, ammonia, nitrite and nitrate.  (see our training material for recommended parameters)
  • Add extra, additional aeration from a different source. There cannot be too much dissolved oxygen in the water.
  • If there is an identifiable bully in the tank, remove the offending fish. (maybe to the dinner plate)
  • Reduce the frequency of opening and closing the lid on the tank. Minimise scooping fish out to inspect them. Only do this if really necessary.
  • Once a disease problem is identified, treat early rather than late.

Next newsletter we will deal with another common difficulty for our Aquaponics Fish.
If you can, attend one of my training courses to get detailed information on how to have a very successful Aquaponics system.
Regards Murray.

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Protozoa, and Nematodes – Tonic for Aquaponics Systems.

The question is often asked if there is a need to add mineral and nutrient supplements to Aquaponics systems. The answer is yes if you want to have nutrient dense vegetables.


Seasol seaweed extract.

In the very beginning, I advocate the use of a seaweed extract such as Seasol for an initial boost in a new system.  It gives the new system something to work on and acts as a tonic for the Aquaponics system aiding in the establishment of the beneficial bacteria.  It is a very gentle and safe way to get your Aquaponics system started.

A new Aquaponics system needs time to develop all the bacteria and microbes that will convert and release the necessary nutrients for good plant growth.

Aquaponics systems closely mimic nature in the way they handle and provide nutrients for the plants. Eventually there is a myriad of bacteria and other microbes that do their job, just as they should in a mature Aquaponics system.

The job of the two main beneficial bacteria in converting the ammonia produced by the fish to nitrates is very obvious. They are established in a new Aquaponics system usually within a few weeks. It takes time for all the other natural processes to develop and establish.

This is the amazing thing about Aquaponics . The way it becomes so balanced and complete.  Never forget, the beauty of Aquaponics is that it is an ECO system. Aquaponics utilises natural processes. The beneficial bacteria, fungal hyphae, protozoa, and nematodes will take up residence in the gravel media beds and do their job of creating nutrients and having them distributed around the system by the moving water

I also advocate the use of “worm extract” or “worm juice or tea” as it is sometimes known. This is done to help “kick start’ the mineral and trace element build up in your new system. Worm tea is not always available to you so the Seaweed extract is a good thing to use in getting your new Aquaponics system up and running.
It should be applied at the rate of a CAP full a day.  This can be continued right up to and past when you add the new fish to your Aquaponics system.  Seasol will not harm the fish. We have tested and used Seasol for more than six years in our Aquaponics systems and are very satisfied with the results.  Natural organic mineral supplements like Seasol work slowly and are not like chemically derived fertilisers.

Seasol or Maxicrop in the USA if you cannot source my favorite product Seasol.  Seasol can be applied once every month or two to a mature system and as above for a new system.  This will assist in a balanced mineral load and as a tonic for the Aquaponics system. It is a good idea to add it at the grow bed water entry point and allow it to peculate down through the grow media and make it’s way around the system carried by the water.

You may find it a good idea to add a half a teaspoon of Chelated Iron to one of the grow beds once a month. Iron deficiency is often encountered in new systems. This is most often a symptom of “Nutrient Lock Out” caused by pH above 7. As pH stays above 7 nutrients are locked up and are not available to the plants even though they may actually be in the system.

Aquaponics systems run best at pH 6.2 to 7.0.

If adding Iron, just use a little water to wash the Iron down in amongst the grow bed media. The Chelated iron can also be added straight down into the water beside the auto siphon device.
This way the iron will be dispersed more slowly around the bed/s. Even though it is added to just one bed, it will find its way around through the entire system.

Potassium and Calcium are also needed in Aquaponics systems. If feeding your fish on commercially available pellets these two elements are often in short supply in your aquaponics system.  Once again, potassium is present in Seasol.

Another way to boost trace elements and particularly potassium and iron is to add some raw molasses to the system water.  Two tablespoons per 1000 ltr (250 gal) It will turn the water a little dark in colour but will clear after a few days.  Molasses is also a sugar so the beneficial bacteria will also get a boost because of the addition of molasses to your Aquaponics system.  It is perfectly safe for your fish

These two elements are easily supplied as part of pH control / adjustment.

Murray Hallam’s Practical Aquaponics.



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