Thanks to JCO, the DIY Aquaponics forum owner, for putting up this area so I could post this series of articles.

This is the first of a series of posts that are going to teach you most of what you would need to know about Aquaponics in order to build and maintain your own system. So, if you're curious about the most amazing food growing technology on the planet today, read this series of educational posts on Aquaponics.

These articles were originally written to address those who are of the belief that we are about to see some serious changes in our economy, along with the price and availability of food. With this in mind, I felt it was time to write this primer to Aquaponics so that those who wish to prepare could have a year round capability for helping to feed themselves and their family.

As these articles progress, I will be talking about family sized systems and focusing on the type that I know best. I realize that there are a number of viable approaches to building Aquaponics systems that many Aquaponic pioneers have experimented with and developed. Due to this emerging technology, there are many differing opinions held by those involved in this wonderful gift of nature. I can only tell you what I believe to be true from all that I have read about other's efforts and from my own experience. Historically speaking, Aquaponics as a technology has been around for a hundreds of years; but ironically, it also is still in its infancy as a family food growing technology. There is still much research to do in this area and much to learn.

These posts are aimed at those who want to build their first system and have the best chance of it working well and producing food.



What is Aquaponics and why should I care?

Aquaponics is an ancient food growing technology that has been around since the Earth has had water with fish and plants growing together naturally. Aquaponics is nature at work. In nature, the fish eat whatever they find for food, and their waste is broken down by the bacteria in the water creating nutrients for the plants. The plants then absorb these nutrients; and in doing so, they help clean the water for the fish.

The word "aquaponics" comes from two separate words. The first word is "aqua", which, of course, means water; but in this case, the "aqua" is from another compound word "aquaculture" (the raising of fish). The second word is "ponics", which is latin for work, and comes from its use in "hydroponics" (working at growing plants in water, hydro).

So, aquaponics is raising fish and growing plants by using the nutrient rich water provided by the fish.

The reason one should care about aquaponics is that it is a year round food growing technology, which can supply you and your family with fresh veggies and fish regardless of the season. Most fish species take a year or more to grow out to edible size. Because of this long term growth, the system must be placed in an environment that allows for year round operation. In tropical climates, an aquaponics system can work outside with minimum cover. In milder climates, it must be placed in an environmentally controlled green house. In harsh climates, it must be placed indoors with grow lights to replace the sun and grow your plants.

The plants grown in an aquaponic system grow out in less time, grow year round, can be planted more densely, are tastier and require 90% less water than does tillage farming. Also, if the aquaponics system is properly designed, it takes up much less space than does tillage farming. Some plants can be grown directly in the fish tank to absorb the nitrates from the water as any one who owns an aquarium knows. Most aquaponics farmers separate their fish tanks from their plant grow beds allowing them more flexibility in the way they grow and in what they grow. The water is circulated between the fish tank and the grow bed using a pump. This is known as a recirculating aquaculture system that contains two food sources, fish and vegetables. Some grow their fish for food while others keep their fish as pets that also serve a useful purpose, which is fertilizing the plants.

But there is a third living organism in the aquaponics equation, the beneficial bacteria. They are the pro-biotic of the system and live in what is called a bio-filter. Just like the name says, the biology (bacteria) filters the waste in the water, not by removing it, but by converting it into nitrates. It could be called a bio-converter but it is called a bio-filter instead. In an aquarium, where there are only a few fish for the amount of water, the bacteria live in the water, the sand on the aquarium bottom and on any surface where they can attach themselves. In an aquaponics system, the amount of fish per gallon of water is much higher than what is usually found in an aquarium. This higher density requires an additional amount of filtration; therefore, a separate bio-filter becomes part of the recirculating water path in the system.

Before discussing bio-filtration, I want to address the concern some may have for the high density of fish in the system. In a backyard or home aquaponics system, we are talking about one pound of fish for about every six gallons of water maximum at full fish growth. Commercial fish farmers usually run much higher densities, which requires special filtration and oxygenation of the water. Even at six gallons per pound of fish in the system, the fish tend to school together somewhat because it's the nature of fish to create schools. They were introduced into the same tank when the were very small, grew up together and like to hang out with each other. When fish get stressed, you will know it by their unnatural behavior. At these densities, your fish will appear relaxed and healthy. I will be discussing the fish in much more detail in a later segment.

The fish give off two types of waste, which, if allowed to accumulate, is toxic to them. As with any living organism, fish cannot live in their own accumulated waste. The first type of waste is ammonia, which is secreted from the gills and found in the fish urine. The second type is fish waste solids. We refer to this as fish poo.

The required bio-filter is a part of the aquaponics system. In many systems, media filled grow beds double as the bio-filter because they have a large amount of surface (substrate) area and function not only as beds within which to grow the plants but also as a place where most of the bacteria in the system live that convert the ammonia. These bacteria, known as autotrophic bacteria, attach themselves to any surface they find. Their job is to convert the ammonia into nitrates. This is a two step process. First, one type of autotrophic bacteria converts the ammonia to nitrites by splitting the ammonia into nitrogen and hydrogen. The nitrogen (N) is then combined with oxygen (O2) found in the water in the form of dissolved oxygen and in this process forms nitrite (NO2). For the chemists reading this, it is NH3 or NH4 + O2 -> NO2 + H2. Both the nitrite and the hydrogen are released back into the water.

The nitrites (NO2) produced are also toxic to fish in relatively small quantities, just like the ammonia. So, the second bacteria comes into play to add some more oxygen to the nitrites converting them into nitrate (NO3). Note the spelling, nitrite (NO2), nitrate (NO3). Now, nitrates (NO3) are not very toxic to fish and generally, depending on the species of fish, they can tolerate 100 times more nitrates in the fish water than they can ammonia or nitrites. Remember, plants need and love (absorb) nitrates, so the nitrates won't stay or accumulate in the water to high levels unless there are fewer plants than needed to absorb (uptake) all the nitrates generated by the fish and bacteria processes in tandem.

This brings us to the solid fish waste. The good news is that nature provides. In this case nature provides us with another type of bacteria known as heterotrophic bacteria. Heterotrophic bacteria live in the water and attach themselves to any dead organic matter like uneaten fish food, dead plant roots or solid fish waste. Through a process called mineralization, the heterotrophic bacteria convert these leftovers into their component parts, which become nutrients for the plants. They also produce their own waste, which is ammonia; and it is converted by the autotrophic bacteria mentioned above into nitrates for the plants. In addition, heterotrophic bacteria help keep the water in the fish tank clean and clear. Heterotrophic bacteria also require and consume the dissolved oxygen in the water in order to live and do their work. So, heterotrophic bacteria take organic suspended solids in the water and convert them to dissolved solids that can be utilized by the plants.

It is important to note that the above processes each require and use dissolved oxygen found in the water (as do the fish and plants) and deplete it from the water as they go about their business. This dissolved oxygen must be replaced on a continuous basis or the process will not work properly. I will discuss the importance of ample dissolved oxygen in your system in a follow up post.

The plants, which are planted in the grow beds, receive the nutrient rich water containing all these wonderful ingredients including dissolved oxygen, uptake them along with some water and use them to grow. The remaining water now has reduced amounts of nutrients, and it is returned to the fish tank for use by the fish. So, the fish are fed, and their waste feeds the bacteria. The bacteria convert their food (fish waste) into bacteria waste that feeds the plants. The plants uptake the nutrient rich food provided by the bacteria. The water is cleaned in the process and returned to the fish. These symbiotic relationships are on-going as this is a recirculating aquaculture system that has both fish and plants as well as natures gift of beneficial bacteria working away, and it is known as Aquaponics.

Part Two will deal with System Design.