Aquaponics: Points for Building an Aquaponics System

The combination of aquaculture and hydroponics creates aquaponics, which is a polyculture system. Aquaponics plays a role in sustainable intensive agriculture, especially in small-scale applications. It can grow a large amount of food in areas where traditional agriculture is challenging or impossible, and it fosters collaboration between vegetable and fish production. In terms of the environment, aquaponics prevents water pollution and escape of wastewater from aquaculture. It also allows for better water management and productivity. Additionally, aquaponics avoids the use of fertilizer chemicals, pesticides, or herbicides, thus preventing any residue.

In aquaponics, the nitrogen cycle is an essential part of the biological process involved, known as nitrification, which occurs naturally in nature. The concept is based on the idea that when fish release nutrient-rich waste, it can serve as fertilizer for plants while also filtering the water for the fish. The process begins with Nitrosomonas bacteria breaking down the fish waste, which primarily consists of ammonia (NH3), into nitrite (NO2). Then, the second type of bacteria, Nitrobacter bacteria, convert the nitrite (NO2) into nitrate (NO3), which becomes the dissolved nutrients necessary for the thriving of hydroponically grown plants. This system operates on the principle of symbiosis and cooperation between fish, plants, and bacteria, ensuring a harmonious balance and creating a favorable environment for healthy growth.

To set up an aquaponics system, several basic components are needed. This system utilizes Recirculating aquaculture systems (RAS), which are self-contained environments for growing aquatic organisms. The essential elements of an aquaponic system include fish tanks, water and air pumps, units for removing solids such as drum filters or settlers, biofilters, plant grow beds, and plumbing materials for water supply. When it comes to water management, there are two types: closed-loop (coupled system) and open-loop (decoupled system). In a closed-loop system, water continuously circulates from the RAS to the hydroponic unit and then back to the RAS. On the other hand, in an open-loop system, also known as decoupled aquaponic systems (DAPS), water is separately recirculated within each system. It is supplied on-demand from the RAS to the hydroponic unit but does not flow back to the system. The connection between the RAS and hydroponic unit in DAPS is facilitated by a one-way valve.

Aquaponics utilizes several types of hydroponic systems. One such system is the Nutrient Film Technique (NFT), where plant roots are suspended in channels called valleys. These channels allow a thin layer of nutrient-rich solution to flow, ensuring the roots remain moist without becoming waterlogged. Another commonly used system is the Media bed technique, which serves as both a mechanical and biological filter while also supporting the plant roots. This design is particularly popular for smaller aquaponic setups. Additionally, the Deep-Water Culture (DWC) method, also known as the raft method or floating system, involves circulating nutrient-rich water through long canals at a depth of approximately 20 cm. Rafts made of polystyrene are then placed on top of the water, floating and sustaining the plants.

The preservation of water resources is one of the advantages of the aquaponics system. It also has reduced operating costs when compared to aquaculture or hydroponics used separately. The system has a high level of biosecurity that aims to minimize the risk of transmitting infectious diseases and contaminants. Additionally, it allows for the recycling of non-renewable resources like phosphorus and potassium, as well as the recycling of renewable but scarce resources like water. The aquaponics system is able to operate in various climates and can be implemented in both rural and urban settings. It is capable of producing food for families or income crops efficiently, and it also provides an efficient use of nutrient sources from fish feed.

Aquaponics System

The main components of an aquaponics system are a fish tank and a grow bed. The fish tank serves as the habitat for the fish, while the grow bed functions as the area for cultivating plants.

The fish tank and grow bed are linked by a pump that transfers water from the fish tank to the grow bed. Afterwards, any extra water from the grow bed flows back to the tank, providing benefits to the fish.

For an aquaponics system to be successful, it is crucial to maintain a harmonious relationship between the fish and the plants. All elements, including fish, plants, water temperature, and tank environment, must mutually support one another. Failure to achieve this balance will result in detrimental effects on both the fish and plants.

First, it is advisable to begin with plant types that do not necessitate a large amount of nutrients in order to thrive. These plant varieties consist of cucumbers, lettuce, watercress, herbs, and cauliflower. Once your system achieves equilibrium and sustainability, you can progress to cultivating plants that are richer in nutrients such as tomatoes, peppers, eggplant, and ginger.

Aquaponics Fish Tank

Choosing the right size and type of fish tank is a crucial decision when setting up an aquaponics system because it serves as the heart of the system and provides a habitat for the fish.

The number and type of fish you want to keep determines the size of the fish tank you should use. A general guideline is to add one inch of fish for every gallon of water. For a 20-gallon tank, you would need either 20 one-inch fishes or 10 two-inch fishes.

To maintain clean and healthy water for the fish, it is crucial to ensure proper aeration and filtration in the fish tank. By having a well-aerated aquaponics tank, you can ensure that the fish are able to respire without difficulty, the plants receive the necessary nutrients, and a mutually beneficial relationship is established between the plants and fish.

Before delving into the specifics of aeration, it is important to examine the three methods by which a tank can be aerated. These methods include mechanical aeration, diffused air systems, and water pump systems.

Mechanical aeration systems: This approach uses a paddle wheel, spinning blade, or similar object powered by a submersible motor to propel water in the tank. This keeps the water fresh and ensures fish waste isn’t accumulating in clumps or corners of the tank.
Diffused air systems: A diffused air system makes use of an aquarium bubbler, otherwise known as an air stone, to transfer dissolved oxygen into the tank water. This is a less abrupt way to keep water fresh for the fish while ensuring the plants still get what they need. Air stones also look great and enhance the visual appeal of your aquaponics tank.
Water pump systems: This is the most complex type of aeration system but also works great for spherical or loop tanks. Water pump systems involve drilling small holes into a pipe that’s submerged in water and later connected to a motor that pushes water through the system. Pumps work well in loop-style tanks because the water has to circulate through the entire tank to be fresh and oxygenated.

After understanding the basics of aeration, it is now important to consider ways to maintain the cleanliness and freshness of your tank. The following are our top recommendations:

Create and use a tank cleaning checklist. Even with thoroughly aerated water, your tank is going to accumulate biowaste, fish solids, and slime. It’s important to regularly clean your tank and its components and drain it fully once per year. The most important aspects to check and clean on a regular basis are your aeration system, its motor, any pipes, and any filters.
Develop a daily maintenance checklist. Several crucial water characteristics should be checked daily to ensure a healthy environment for plants and fish. Those factors are the water’s alkalinity, dissolved oxygen, nitrogen, temperature, and pH. Here’s what each component should be:

Alkalinity: 100 ppm CaCO3 or greater
Oxygen: 5 mg per liter / per quarter gallon
Nitrogen: 3 to 150 mg per liter
Temperature: Between 68°F to 86°F / 20 to 30°C
pH: Between 6.8 and 7.0 (ever so slightly acidic)

Use the right temperature and pH level. Water pH and temperature levels are crucial to ensure both plants and fish are getting what they need. A healthy pH level for most aquaponics systems is between 6.8 and 7.0. The right temperature range is about 68°F to 86°F, or 20 to 30°C. This range is where the fish, plants, and bacteria do best, optimizing your system for months to come.
Maintain a well-ventilated system. Just like the water needs to be well-oxygenated, fresh air is essential too. If your system is outdoors, this is typically all the ventilation you need. If you’ve set up aquaponics indoors, make sure it’s in a room that receives predictable airflow. If this isn’t the case, set up a fan or a timed source of air circulation that ensures the room isn’t getting stale.
In general, maximize your tank’s aeration. The more aerated your tank’s water is, the more your plants and fish thrive. Without fresh oxygen, your fish will suffer, and potentially die, and your plants will also wither. As long as your aeration system is running smoothly each day and you clean it at least once per month, you’re on the right track.

Aquaponics DIY Tips

Now that you have a understanding of the fundamentals of an aquaponics system and how to maintain it, let’s delve into some do-it-yourself suggestions. Below, we will share the techniques and recommendations we have personally implemented in our aquaponics systems.

Create a budget. Just like any other goal, a well-organized budget makes it much easier to accomplish. You can get a quality, reliable, at-home aquaponics system started for about $1,600 to $3,000.
Designate a space for your system. Aquaponics can work both outdoors and indoors but we recommend indoors for beginners. This gives you more control over the setup and helps you monitor both plant and fish needs in a simpler manner.
Research the fish you want. There are dozens of fish varieties that work for aquaponics but that doesn’t mean you should blindly choose any. Consider what kind of fish match your aquaponics goals and what their needs are. Look at what’s feasible based on your aquaponics budget.
Get the right equipment. Your aquaponics system needs plenty of hardware to get up and running. The essentials include the fish tank, a grow bed, a water pump or aeration system, grow media, PVC pipe including fittings, bulkheads or uniseals, a seed starting tray and seed starting cubes, a siphon, a water testing kit, a total dissolved solid (TDS) or electrical conductivity (EC) meter.
Set things up properly. With your equipment and space prepared, it’s time to get things organized. Use the instructions and information that came with your equipment to set it up correctly. If you bought an all-inclusive aquaponics kit, follow the steps in the instructional info it comes with.

Best Fish for Aquaponics

It is essential to carefully select fish for your aquaponics system, considering your home’s climate, average temperature, and tank size. By researching the specific type of fish you desire and ensuring compatibility with your tank setup, you guarantee favorable outcomes.

The following types of fish are considered the best for aquaponics.

Trout

Advantages: Work well with a varied diet; easier to maintain in colder climates
Drawbacks: Grow slowly; need large tanks; can’t be grown with other fish; need a higher level of dissolved oxygen

Catfish

Advantages: Easier to grow and breed; aren’t territorial; can be grown in varying water temperatures
Drawbacks: Can be easily stressed or injured; must be fed high-protein foods

Tilapia

Advantages: Grow quickly and in a variety of environments; they’re top feeders (quickly adjustable diet)
Drawbacks: Quick reproduction timeline; requires warmer water in a climate that is still cool

Goldfish

Advantages: Handle different pH levels well; produce waste frequently for plants/grow bed
Drawbacks: Can’t be mixed with other fish

Salmon

Advantages: Tolerate cold temperatures/climates well
Drawbacks: Require more food; more likely to contract disease than other fish

Advantages: Resist diseases and parasites well; long lifespan
Drawbacks: Need a large tank; produce more waste as they age creating a greater need for maintenance

Largemouth bass

Advantages: Top feeders; work well with a varied diet
Drawbacks: Require close monitoring of potassium levels; very sensitive to environmental changes; don’t tolerate bright light

Aquaponics Setup

Once you have prepared your aquaponics materials and fish, you can proceed with setting up your aquaponics system. The initial stage involves the correct installation of both the fish tank and the grow bed. It is crucial to ensure proper connection of the tank and the bed with the pump, and to confirm that the water is being effectively filtered and aerated.

Second, is ensuring your hardware is set up and running correctly before adding fish. That way your fish aren’t experiencing shock or potentially dying because the tank’s environment wasn’t ready.

Next, it is essential to ensure that your system is adequately balanced between the fish and the plants. It is important to avoid an excessive or insufficient quantity of either component, as this will result in unfavorable outcomes.

Aquaponics Tank

In your aquaponics system, the tank holds significant importance as it serves as a habitat for the fish. It is vital to select an appropriately sized and shaped tank for the desired type of fish and to ensure proper aeration of the tank.

How to Build an Aquaponics System

If you prefer to purchase supplies individually and construct your own tank, that is also perfectly viable. Although building an aquaponics system may initially appear intimidating, it becomes easy once you start.

Assemble the hardware. The tank itself, filter, aerator, any electrical components, pipes, and any other pieces must be assembled before anything else can be added.
Put your media bed together. Media is the material used to grow your plants without soil. This keeps your plants’ roots positioned correctly while ensuring they still receive the nutrients required for growth. Start with a 1:1 ratio of bed volume to fish tank volume, and as your system matures you can increase that to 2:1.
Add fish to the tank. When your tank and media bed are assembled, test your tank water first. When it passes all tests, you’re clear to add your fish.
Add your seed cubes or plant starters. Now that everything else is ready you can add your plant starters or seed cubes. Make sure your plants receive the care and handling necessary for their growth.

Now, you are ready to start! Continue to observe your fish and plants for both anticipated actions and unforeseen events. Adhere to your regular maintenance schedule on a daily, weekly, monthly, and quarterly basis and you will soon enjoy all the benefits of aquaponics.

Drawbacks of Aquaponics

Despite its numerous advantages, aquaponics unfortunately has some drawbacks. It is important to be aware of these key drawbacks as they can help you determine whether or not investing in aquaponics is still desirable.

Heavy reliance on electricity. In order for the pumps and filters to operate effortlessly, they require electricity. For those 100% reliant on solar power, this may not be as much of an issue. For individuals and families already on a tight budget, this will only spread them thinner.
Limited plant selection. While aquaponics greatly reduces the amount of water needed for growing, you can’t grow a variety of plants with it. You’re limited to the plants that can do well with growing bed media and a constant supply of water. For most people, this ends up being plants like cucumbers, lettuce, watercress, cauliflower, and cabbage.
High startup costs. Even if you’re setting up a modest home aquaponics system, it can cost more than $1,000. Most people will need to invest closer to $2,000 to $3,000 for all the equipment necessary to sustain great results. This cost is feasible for families with the means but can be a high barrier to entry for those looking for an inexpensive hobby.