What Is Aquaponics?
Aquaponics is a sustainable food production method that combines aquaculture (raising fish) with hydroponics (growing plants without soil) in a symbiotic closed-loop system. Fish produce ammonia-rich waste, which beneficial bacteria convert into nitrates, a form of nitrogen that plants absorb as fertilizer. The plants, in turn, filter the water, which is returned clean to the fish tank. This cycle mimics natural ecosystems and produces both protein (fish) and vegetables with remarkably efficient use of water, space, and nutrients.
IBC totes are the most popular container for DIY aquaponics systems because they provide generous volume for both the fish tank and the grow bed at a fraction of the cost of purpose-built tanks. A single 275-gallon IBC can be cut to create a 175-gallon fish tank (the bottom portion) and a 12-inch-deep grow bed (the top portion), providing a complete, self-contained system from one container. This affordability and versatility have made the 'IBC aquaponics system' one of the most searched DIY projects online.
Selecting and Preparing the IBC
For aquaponics, the IBC must have held only food-grade or non-toxic products. This is absolutely critical because any chemical residues will enter the water, poisoning the fish and contaminating the plants. Totes that previously contained vegetable oil, fruit juice, vinegar, or food-grade glycol are ideal candidates. Never use a tote that held industrial chemicals, pesticides, solvents, or any product you would not want in your food chain.
Thoroughly clean the IBC before cutting by rinsing with hot water and food-safe cleaner at least three times. Drain completely and allow to dry. Some aquaponics builders add a dilute vinegar or citric acid rinse as a final step to remove any mineral deposits or residual film. Once clean, mark your cut lines using a level and marker. The standard cut for a one-IBC system is a horizontal cut across the bottle approximately 12 to 14 inches from the top, creating a shallow grow bed tray and a deep fish tank section.
Use a reciprocating saw, jigsaw, or angle grinder with a cutting disc to make the cuts. HDPE cuts easily but produces sharp edges; sand all cut edges smooth with 80-grit sandpaper to prevent injury and to provide a clean surface for any fittings you will install. The steel cage should be cut with an angle grinder at matching heights. Save all cage sections, as the upper portion can be inverted to serve as a stand for the grow bed above the fish tank.
System Design and Plumbing
The most common IBC aquaponics design is the media-based system, where the grow bed is filled with an inert growing medium (expanded clay pebbles, lava rock, or gravel) that supports the plants and houses the nitrifying bacteria. Water is pumped from the fish tank to the grow bed, percolates through the media, and drains back to the fish tank through a bell siphon or timed-drain mechanism. This flood-and-drain cycle aerates the roots, distributes nutrients, and provides the wet-dry cycling that nitrifying bacteria need to thrive.
The bell siphon is the most elegant drainage solution for media-based aquaponics. It is a simple device that uses siphon physics to automatically flood the grow bed to a preset level and then rapidly drain it, with no moving parts, electronics, or timers required. The siphon consists of a standpipe, a bell (an inverted pipe that covers the standpipe), and a media guard to keep growing medium out of the mechanism. Building a reliable bell siphon requires attention to pipe diameters and heights, but numerous free design guides are available online with specific dimensions for IBC-based systems.
A submersible pump in the fish tank drives the system. For a single-IBC system, a pump rated at 200 to 400 gallons per hour is sufficient. The pump should turn over the fish tank volume at least once per hour for adequate filtration. Connect the pump to the grow bed inlet using 3/4-inch or 1-inch PVC pipe or flexible tubing. Include a ball valve on the pump outlet to adjust flow rate, and install a screen or pre-filter on the pump inlet to prevent debris from clogging the impeller.
Choosing Fish and Plants
Tilapia is the most popular fish for aquaponics due to its hardiness, rapid growth, tolerance of crowded conditions, and excellent eating quality. They thrive in water temperatures of 75 to 85 degrees Fahrenheit and can reach harvest size (1 to 1.5 pounds) in 6 to 9 months. However, tilapia are tropical fish and require heated water in Tennessee's climate during cooler months. Other warm-water options include catfish, perch, and largemouth bass, each with different temperature and stocking density requirements.
For cooler environments or unheated systems, trout and other cold-water species are viable when water temperatures remain below 65 degrees Fahrenheit. Goldfish and koi are popular for ornamental or non-edible aquaponics systems; they are extremely hardy, tolerate a wide temperature range, and produce abundant waste to feed the plants. Beginning aquaponics practitioners often start with goldfish to learn the system dynamics before transitioning to edible species.
Leafy greens are the easiest and most productive plants for aquaponics beginners. Lettuce, kale, Swiss chard, basil, mint, and other herbs grow prolifically in media-based systems with minimal attention. Fruiting plants like tomatoes, peppers, and cucumbers can also be grown but require more established systems with higher nutrient levels. Avoid root vegetables like carrots and potatoes, as the growing medium does not allow proper root development for these crops.
Cycling the System and Water Chemistry
Before adding fish, the system must be 'cycled,' which means establishing the beneficial bacteria colonies that convert toxic ammonia to nitrite and then to nitrate. This nitrogen cycle is the biological engine that makes aquaponics work. Cycling typically takes 4 to 6 weeks and can be initiated by adding a small amount of pure ammonia (available as unscented household ammonia) to the system to feed the bacteria. Monitor ammonia, nitrite, and nitrate levels daily using an aquarium test kit.
The cycle is complete when ammonia and nitrite levels consistently read zero within 24 hours of adding ammonia, and nitrate levels are rising. At this point, the system can support fish. Start with a light stocking density, approximately one fish per 5 to 10 gallons of tank volume, and gradually increase over several weeks as the bacterial colony matures. Overloading the system with fish before the bacteria can handle the waste load is the most common cause of fish loss in new aquaponics systems.
Maintain a pH between 6.8 and 7.2 for optimal balance between fish health, bacterial activity, and plant nutrient uptake. Use potassium hydroxide or calcium hydroxide to raise pH and phosphoric acid to lower it. Avoid using citric acid for pH adjustment, as it can inhibit nitrifying bacteria. Regular water testing and gradual adjustments are key to a stable, productive system.
Getting Started with IBC Aquaponics
An IBC aquaponics system can be built in a weekend with basic tools and plumbing skills. The total cost for a complete single-IBC system, including the tote, pump, plumbing, growing media, and test kit, typically runs between $200 and $400, making it one of the most affordable entry points into home food production. The system can produce lettuce year-round in a greenhouse or sunroom, supplemented by fish harvests every six to nine months.
ABC IBC is proud to supply clean, food-grade used totes to the growing aquaponics community in Nashville and across Tennessee. We help customers select totes with appropriate prior contents, inspect for condition and age, and share the knowledge we have accumulated from years of working with IBC containers. Whether you are a backyard hobbyist or a school setting up an educational system, we have the right tote for your aquaponics project.