Hello to all! First, I want to apologize for being a little slow in getting out some blog updates with some awesome content. As you know, I love providing great information that will help you become a successful aquaponics grower! My heart's desire is to spread this worldwide! We are in over 75 countries and it’s growing. Daily, I am conversing with someone regarding aquaponics. I have a teacher in El Salvador preparing for a multi-national science fair they are hosting. She is building her very own aquaponics system. Very exciting for us here at MorningStar Aquaponics that we can be a part of an event such as this.
I am super excited to announce that will be soon releasing a new FREE E-book on “Plant Nutrients and Deficiencies. I can’t tell you how many times I have seen on Facebook with new aquaponic growers asking the community what’s wrong with their plants and uploading pictures. Then to see people offering the WRONG advice. Sometimes, making matters worse!
See, if you don’t know what you are doing in the area of system supplementation, you can not only diagnose your deficiency wrong, but you can add the wrong supplementation. Or you may diagnose the issue incorrectly but add the wrong supplementation and ultimately locking out other nutrients to the plants.
It can kind of get messy in the aquaponics world. Well, we want to help put and an end to that. About two weeks ago, I began writing this e-book. What started out as a mini-informational guide has now turned into a book! BUT, that’s me, a perfectionist and never happy. I want this so complete that after reading it, you will become confident in making the right decisions for your system.
So, stay tuned! In another few weeks, for those of you subscribed to our blog, you will receive this e-book via your email. As always, Happy Aquaponics!
Credit: financialmail.com by LONDIWE BUTHELEZI
Just outside Pretoria, a 1ha farm is producing 5t of fish using just 1% of the fresh water a traditional farming operation would need. And it’s growing vegetables, using the ammonia-rich water from the fish tanks for irrigation, then distilling the run-off and piping it back to the fish tanks in a never-ending cycle.
It’s a sophisticated operation, with technology that allows sensors to be activated remotely to monitor the fish and plants, turn water pumps on and off, and alert farmworkers if the fish are in danger or distress.
"It’s a completely self-sustainable turnkey model," says Leon van Deventer, agricultural engineer at technology company Matsei, which runs the pilot farm alongside Swedish enterprise software company IFS. "You can put it in the middle of the desert because all you need is solar energy and satellite communication to monitor sensors on the plants and fish tanks, and you use so little water."
It may be difficult to get one’s head around the idea of farming in a desert, but Sundrop Farms has proved it’s possible in south Australia. Since 2016 the company has been producing 17,000t of tomatoes a year using just sunlight and seawater.
While Sundrop’s system involves hydroponics — growing plants using a nutrient-rich, water-based solution rather than soil — IFS and Matsei are using aquaponics. A hi-tech version, at that.
Aquaponics brings together conventional aquaculture, such as raising fish in tanks, and hydroponics. Popular with missions and government aid initiatives, it produces more food using less water than traditional agriculture. And it uses just 1% of the land to produce the same amount of protein as a herd of cattle. Aquaponics farmers source fingerlings — juveniles of resilient species such as catfish — and feed them in a controlled environment until they reach the right weight for consumption.
Despite its efficiencies, it hasn’t gained traction in SA — just a few farmers are doing it, and then on a small scale. Van Deventer believes this is because aquaponics needs the entire production ecosystem — farming, processing, storage and transportation — to be in place in the community where the farm is.
However, agricultural economist Wandile Sihlobo says the issue is one of cost: because there’s ample open land still available for growing produce in SA, the cost of aquaponics counts against it. "If competition for land toughened, you would see aquaponics take off," he says.
Sihlobo believes concerns around climate change — and resultant concerns around food security — will drive the adoption of new agricultural methods, including aquaponics. "But the cost has to come down first, and I expect that it will in coming years."
Food security is at the heart of the IFS/Matsei project. The joint venture will focus specifically on rural communities, with the aim of promoting sustainable food production in poor communities, while offering a cheaper source of protein.
"It’s easy for communities in Africa to cultivate starch such as maize," says Van Deventer. "The problem lies in getting meat-based protein, and we know red meat is costly for many, even the middle class." Read the remaining article: CLICK HERE
This is section 2 of Part 3 in our “Key Elements of Water Quality.” Last time we talked about aeration and dissolved oxygen (DO). We covered the aspects of DO and the important role it has with fish, bacteria, and plants. I recommend that you go back and read that posting, Aeration - Section 1. Also, there are previous articles in this series - “Water Purity” and “Water Temperature.”
As stated before, we have covered DO, but now we want to discuss ways of adding oxygen to your system. Fish in their natural habitat, oxygen is supplied either by aquatic plants that produce oxygen through photosynthesis or from water movements such as waves and wind that dissolve atmospheric oxygen into the water. That can be the case in aquaponics to a minimal degree. Because of fish density and bacteria dependent upon DO, you must take extra steps to ensure your system has the proper amount.
Aquaponic growers that are a hobbyist and have less than commercial size systems have relative ease in supplying the proper amount of DO needed. In our e-book, “Step by Step Aquaponics, Simplifying the Building Process for You.” The systems we feature in the e-book takes proper precautions a grower must perform in providing DO needed for the fish, bacteria, and plants. Commercial systems can be much more complex for various reasons, but one being the stock density of the fish.
Today, we will talk about two ways to aerate your system and they are easy to perform. Under normal circumstances, you will not have any issues with DO unless you have a dramatic rise in water temperatures. If that is the case, the DO needs to be supplemented through management strategies.
In your system, you need to ensure that there is proper aeration in the fish tanks, bio-filter, and grow beds. By doing so, this will make sure that all forms of life are getting the required amount of DO, which is 5-8 ppm. Side note, I make sure my sump pit is receiving aeration. It’s an area you can capitalize on with little effort.
Two ways for aeration in smaller aquaponic units are to use water pumps to create a water flow, and to use aerators that produce air bubbles in the water. Water movement and aeration are critical components, and their importance cannot be overstated and stressed upon.
Water Pump Driven Aeration
Water pump driven aeration systems would include spray bars, venturis, oxygen saturation cones, and water mixers. Below is the description of each technique:
Spray Bars or Heads - are some of the most common ways to aerate your aquaponic system. It doesn’t require much skill in building them and they are easy to make. The main thing to consider is where you can place a spray bar to effectively break the water surface. In the designs we provide in our e-book, you will do so in the sump pit and fish tank. Below are the photos of the two ways we accomplish this. As you can see, we have a bar traversing across the fish tank. The water is sprayed directly onto the water surface. As it’s doing so, aeration is occurring. The other photo shows the water coming from the grow beds directly into the sump pit. The dump tube has a cap on the end and several perforated holes to allow the water to spray out onto the surface of the water. There are many ways you can customize a spray bar. The main objective is to break the water causing bubbles to form and water movement.
Venturis - are used to “suck” air into a pipe and mix it with water. Medium and high head pumps have enough pressure to allow installation of a venturi device which restricts water flow creating a suction force which draws air into the draft tube above the venturi. The flow of water and the pressure determines how much air can be drawn in. Please note it will reduce the water flow volume and pressure when using a venturi.
Spray bars or heads and venturis are really all you need in a smaller backyard aquaponics system regarding water movement (Note: you will need to add a mechanical aerator as well). There are other applications that can be used but not as common in the world of aquaponics or at least in the backyard builds, they are known as Oxygen Saturation Cones and Water Mixers. Click "READ MORE" in lower right to read the rest of the article.
This is part 3 of our "Key Elements to Water Quality" blog postings. I suggest that you go back to read the others as well on “Purity” and “Temperature.” We are now going to be discussing aeration. I will be dividing this into two sections due to it being such a vast subject.
Dissolved Oxygen (DO) can be a common thing that many overlooks and don’t give it the attention it deserves. Also, when they think about it, they will only consider the fish needing oxygen but do not realize nitrifying bacteria and plant roots need it as much.
When building a system, you need to consider ways to introduce oxygen into the system; that is called aeration. Oxygen dissolves directly into the water surface from the atmosphere through natural conditions, fish can survive in such water. This amount of DO diffusion does not meet the demands of an aquaponics system. It needs additional oxygen in the water to offset the deficit created by the breakdown of waste (fish fecal matter or food), higher temperatures, and consumption by fish, nitrifying bacteria, plants, or any other organisms living in the water such as algae.
Aeration can be performed many ways and we discuss that in the next article. This blog post, I want you to become more familiar with dissolved oxygen and the effects it has on the system. When we talk about DO, we’re talking about the oxygen that is soluble and has dissolved in the water. It is measured by ppm (parts per million) or some will refer it to mg/L (milligrams per liter), which can be used interchangeably.
Low DO levels are not usually a problem with hobby aquaponic growers with low fish stocking rates. The problem tends to arise more in commercial operations with high stocking rates. The systems featured in our “Step by Step Aquaponics” material are designed in such a way to ensure high levels of DO. If you feel you are experiencing lower levels, there is no risk of adding too much oxygen through more aeration; when the water becomes saturated, the extra oxygen will disperse into the atmosphere.
Our recommendation of stocking density is around 1 fish per 5 gallons of water or 20 kg of fish for every 1000 liters of water. When making these calculations, I am only considering the fish tank size. I realize that this may be a conservative approach, but I would rather be cautious. As the system matures, it is safe to increase your stocking density, but you need to continue to monitor the health and wellness of your system by checking your pH, ammonia, nitrites, nitrates, plant growth, and that your fish are not gasping for air on the surface of the water. If you see your fish doing this, you have a DO problem and it needs to be rectified immediately. Click "READ MORE" in lower right to read the rest of the article.
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