Aquaponics 101: The Essentials

What is Aquaponics?

Though plant lifeforms evolved to be suited for land hundreds of millions of year ago, it turns out that water creatures can still form an incredibly beneficial symbiotic relationship with them when given the chance. Evidence shows that some ancient civilizations understood this connection, and over the past 40 years innovative scientists have rediscovered this sustainable farming technique known today as aquaponics. It has only become more popular over the past decade as knowledge of these alternative methods has grown more widespread.

In aquaponics, farmers combine aquaculture (the cultivation of aquatic animals, such as fish) with hydroponics (the cultivation of plants in water) to create a mutually beneficial ecosystem where fish waste provides nutrients for plants, while plants filter and purify the water for the fish. This system mimics natural nutrient cycles, creating a healthy ecosystem in which plants can thrive.

Investing in an aquaponics system provides numerous benefits. First, water is recirculated in aquaponics, which results in significantly less water usage than that of soil-bases aquaculture. Second, with less need for fertilizers there is less risk of water pollution and better overall plant health. Lastly, aquaponics also allows for year-round cultivation and faster plant growth, generating more efficiency and better overall results for the intrepid farmer.

Building an aquaponics system is an involved and multi-step process, and this article will just cover the basic materials you need to get started. To the extent possible, recommendations here are geared toward accessible DIY or backyard set-ups.

Essential Components of an Aquaponics System:

1) Fish Tank: While normal fish tanks can be used, a great option for an outdoor set-up is to use caged Intermediate Bulk Container (IBC) tote tanks (pictured). IBC tanks are durable, cost effective, and can be converted to use in a aquaponics set-up with relative ease. They are scalable and come in different sizes you can fit to your particular space. In a small at-home operation, a single container can even become both a tank and a grow bed by cutting off the top portion of it, turning it over, and placing it above the bottom portion.

2) Grow Bed: In aquaponics, the grow bed can be positioned either above the fish tank or next to it, depending on the type of system you’d like to use. In an ebb and flow system, placing the grow bed above allows water to flow back into the tank by gravity. After the water is pumped up to the grow bed, it naturally returns to the fish tank, creating a continuous and energy-efficient water circulation system. However, there also benefits to Single Loop Aquaponics systems, where a sump tank is placed between the fish tank and grow bed. There are a variety of media to use as bases for grow beds: rockwool, clay pepples, and perlite.

3) Sump Tank: While a sump tank may not be necessary for a small DIY aquaponics operation, it is an important tool if you want to have more grow beds. A sump tank sits at the lowest point and serves as a reservoir to manage and regulate water levels in the system. A sump tank will always ensure a constant level of water in the fish tank, and it will save energy since water can flow back into it from the grow bed via gravity. In addition, a sump tank helps to stabilize the water’s flow and nutrient content for a healthy environment for fish and plants, acts as a debris removal device, oxygenates the water, and facilitates an even distribution of nutrients to plants.

4) Solids Lifting Outlet: When using a sump tank, a solids lifting outlet is an important component for waste and debris removal. It sits at the bottom of the fish tank, where it draws in water and waste that accumulates at the bottom. This mixture is transported to the sump tank, allowing for unneeded solids to be removed from the water before reaching the plants.

5) Pumps: Water and air pumps are necessary to ensure a healthy ecosytem in an aquaponics operation. Water pumps circulate water from the fish tank to the grow bed so that plants can receive their essential nutrients, and air pumps oxygenate the water for the fish.

6) Biofilter: A biofilter is a crucial component that plays a key role in maintaining water quality. Through nitrification, it converts toxic ammonia from fish waste into less harmful substances. The primary function of a biofilter is to provide a habitat for beneficial bacteria that perform the nitrogen cycle, converting ammonia to nitrites and then to nitrates. It contains a medium or substrate that provides a large surface area for beneficial bacteria to colonize. Common biofilter media include plastic bio-balls, ceramic rings, lava rock, and other porous materials.

Where a biofilter is placed really depends on the type and size of aquaponics system one is running. Many aquaponics systems position the biofilter in close proximity to the fish tank, allowing for easy water flow from the fish tank to the biofilter and back. In some systems, the biofilter may even be incorporated as a section within the fish tank itself. In other systems, biofilters may be placed before or after the sump tank or in the grow beds themselves. In media-based grow beds, the media can serve as the biological material for the biofilter and promote the colonization of beneficial bacteria.

5) Radial Flow Settler: This is a device used to separate solids from water. It operates based on the principles of gravity and centrifugal force to allow suspended solids to settle and be removed from the water. The radial flow settler is particularly effective in capturing larger solid particles before the water moves on to additional filtration stages or enters the grow beds in an aquaponics system.

6) Test Kit: Regular water testing is critical to monitor parameters such as ammonia, nitrite, nitrate, and other water quality indicators. Testing kits help ensure that the water conditions are suitable for both fish and plants.

Building Sustainable Gardens

These essential components are just the beginning of your aquaponics journey, but provide a roadmap toward a dependable and functional system. Upcoming articles will explore specific designs for aquaponics systems and any troubleshooting that may be required. Reach out to us, or explore our links for further reading below in order to start digging into this fascinating sustainable farming technique!