How Does Aquaponics Work?

Aquaponics is a symbiotic habitat that blends traditional aquaculture with hydroponics (plant cultivation in water). In this organic setting, excretions from aquatic creatures (snails, fish, crayfish, or prawns) are collected using a hydroponic system that works as a settling basin; the by-products break down as nitrites and nitrates, which are used as nutrients by the plants. As a result, the water with wastes becomes clean because the plants also act as a filter. The entire process, in turn, recirculates filtered water, making it favourable to the plants and other organisms involved.

Why is aquaponics popular?

Over the years, aquaponics has garnered a rising number of worldwide commercial practitioners, which led to a sizable global market value. According to www.businesswire.com, "the global aquaponics market size is valued at $580 million - $630 million as of 2020, as per the findings of this business intelligence report."

Aside from the business side, aquaponics has also caught the attention of educators because it mimics a natural ecosystem where students can witness the integration of Math, Science, Biology, Chemistry, and Technology.

Interior designing enthusiasts have also been hooked into aquaponics. Website articles and video tutorials regarding aquaponics are now available for those who want to use it to beautify their landscapes or improve the ambiance of their commercial offices.

Humanitarian groups use aquaponics to supply people in developing countries with fish and vegetables. This practice is possible because aquaponics setups work anywhere.

There are also hobby farmers who make use of aquaponics in order to produce food products that are free from any form of harmful chemicals. For them, aquaponics is a good use of their leisure time.

But why is aquaponics popular? Here are some good reasons I can think of:

Aquaponics relies on the constant repurposing of nutrient-rich water. Hazardous run-offs produced by hydroponics and aquaculture are taken out of the equation.
Because it functions as a natural ecosystem, no petrochemicals, pesticides, or herbicides can be used.
Scalability is an excellent feature of aquaponic setups. Aquaponics can accommodate most sizes and budgets, from modest countertop herb systems to backyard gardens to full-scale farms.
Gardening chores are drastically reduced or even eliminated. The aquaponics grower can concentrate on the more pleasurable activities of feeding the fish and caring for and harvesting the plants.
By removing the need to turn or plow the soil, aquaponics reduces erosion incidents. Compared to a traditional horticulture farm, the backbreaking effort of changing soil and picking weeds is no longer required, lowering the cost. You can do gardening at a waist level.
Aquaponics can be employed in non-arable environments, including deserts, deteriorated soil, and salty, sandy islands.

What are the different types of aquaponics?

There are three employable setups for aquaponics. These are nutrient film technique, deep water culture, and media bed. Each of these has its own set of advantages and disadvantages you can take into consideration.

Nutrient film technique

The Nutrient Film Technique, also called NFT, is an aquaponics technique in which plants are grown in long pipes. Water films pass through each channel regularly, supplying oxygen and nutrients to the plants' roots. Because there is only a small volume of water (that of a film) and surface area for the nitrifying bacteria to live, the process necessitates using a biological filter.

Pros of Nutrient Film Technique

The roots are highly oxygenated because they are exposed to oxygen that boosts their growth.
Solids build-up is prevented because water is free-flowing continuously inside the pipes.
There is minimized fungal growth because, again, the water is constantly flowing.

Cons of Nutrient Film Technique

The roots of the plants, as they grow, can clog the canals. This situation blocks other plants from getting nutrient-rich water supply.
Since the water flowing through the channels is shallow, as thin as a film layer, it is subject to quick temperature change. Plants do not do well in this type of condition.
The plants that grow in this technique are only those identified as leafy vegetables and herbs. Others that have extensive root systems do not grow well via aquaponics NFT.

Deep water culture

This approach in aquaponics is also called DWC or raft system or float system. Plant roots dangle in nutrient-rich, oxygenated water, absorbing oxygen and nutrients for faster growth. The nutrient-rich water is cycled via long canals at a depth of about 20 cm in a deep water culture method, while rafts (typically polystyrene) that contain the plants float on top. The nutrient-rich water flows continually from the fish tank to the raft tank, where the plants are cultivated, then back to the fish tank. Beneficial bacteria can be found in the biofilter, raft tank, and other parts of the system. Because of its mass-production potential, this technology is commonly used in large-scale or commercial aquaponics.

Pros of Deep Water Culture

There are minute moving parts and assembly that you can monitor easily.
Rapid growth for the plants. One practitioner claims he could harvest lettuce within 30 days compared to a 60-day average cultivation period.
This approach suits commercial aquaponics.

Cons of Deep Water Culture

The water underneath could be a breeding ground for mosquitoes.
Because the roots are immersed, aeration is frequently required to give oxygen.
Your roots may "drown" in low-oxygen nutrition solution if you experience an outage or a pump malfunction.

Media Bed

Media bed aquaponics is an effective setup for small-scale production. Four elements work together in this aquaponics: fish, grow beds, growing media, and plants. These components work together to provide a closed-loop system with the continuous nutrient flow and waste filtering from beginning to finish. The grow bed is a container that stores the growing medium, which might be volcanic gravel or clay pebbles.

Grow medium is used to anchor and support the plant's roots while also functioning as a natural biological filter for all water passing through the system. The fish are kept in separate tanks, and their waste is issued into the grow beds, where it provides essential nutrients to the plants.

Pros of Media Bed

This setup works for plants with a minor or extensive root system.
Red worms can be placed on the gravel bed to help break down fish waste even further.
The presence of air between the media beds supplies oxygen to the roots.

Cons of Media Bed

Not suitable for large scale commercial production
High-end growing media might be costly.
Because the media beds are dense, they require a sturdy, solid structure.

What plants and fish can grow in aquaponics?

Various fish and plants can be grown in aquaponics. I have listed some of them below:

Plants

Crops:

Tomatoes - These grow exceptionally well in aquaponics. They thrive in warm places with nutrient-rich water. To facilitate further their growth, tomatoes require a pH of between 5.8 and 6.8.
Strawberries - Aquaponics is a perfect approach for the soilless growing of strawberries. According to experienced growers, NFT and media beds do well for strawberries. The recommended pH level is between 5.5 and 6.5.
Pepper - Many pepper varieties can benefit from aquaponics, from sweet bell peppers to hot chili ones. Since this plant grows every summer, you must monitor the temperature of your setup to ensure a productive yield.
Cabbage - Not much effort is required for cultivating cabbages via aquaponics. This plant requires scant maintenance on your part. Enough sunlight, pH range between 6.2 and 6.6, along with a temperature of 60 to 70 °F (16 - 21 °C) are all you need to have a bounty of cabbages.
Onions - You can grow onions in any of the three aquaponics setups mentioned above. Typically, onions require around a dozen shoots to develop above ground before planting the next clove. The bulbs in aquaponics can be spaced as close as an inch apart, allowing more to be grown in a smaller space.

Ornamental plants:

Water hyacinth - Aquaponics systems benefit greatly from water hyacinths. This aquatic plant purifies the water in your fish tank. It is an excellent algae removal agent, simultaneously cleaning the water for your fish.
Marigolds - Another ideal houseplant for aquaponics is the marigold. They can be used as a cover crop to keep pests away from your plants. Moreover, beneficial insects will be attracted to your plants as well.
Roses - The Nutrient Film Approach is the most commonly used aquaponics technique for roses when picking an aquaponics technique. As you grow roses, keep in mind that they require enough lighting, so be sure to place them under direct sunlight.
Spider plants - Growing these plants in aquaponics is ideal because they thrive in moister soils. For them to grow exceptionally, ensure that the water has the proper nutrients.
Sunflower - Most sunflower farmers will have these on floating rafts or media beds. Because they can grow rather tall, it is vital to provide support. As their name implies, Sunflowers require a lot of light to grow, so choose a spot that gets plenty of it.

Fish

Edible:

Tilapia - This fish is an all-time favorite for aquaponics practitioners. One common reason is that tilapia has high resiliency against diseases and parasites. They also survive in a wide range of water conditions.
Trout - This fish, especially during the winter, is suitable for aquaponics in Nordic or moderate climates. In comparison to tilapia and carp, trout require a higher protein diet. They can thrive in freshwater, brackish water, and other marine habitats due to their excellent salinity tolerance.
Catfish - Beginners or aquaponics farmers who want to produce fish with an unreliable electricity source should start with catfish. Catfish can be stocked at higher densities with sufficient mechanical filtration due to their high tolerance of low DO levels in waters.
Pacu - This edible fish is grown through aquaponics for two compelling reasons. First, pacus fish are easy to harvest since they are omnivorous and consume different types of food. Second, pacu species grow significantly, up to 25 inches in length.
Salmon - Although cultivating salmon in aquaponics is challenging, growers still choose them since they are healthy and delicious, making them marketable.

Ornamental:

Koi - Because they are so adaptable to their surroundings, Koi are a popular choice for aquaponic gardening. Koi prefer a pH range of 7.5 to 8.5 to grow. While it can withstand a wide range of water temperatures, the optimal range is 35°F to 85°F (2°C - 29°C).
Goldfish - Goldfish are an excellent aquaponics choice. They are not only economical and attractive in your home, but they can withstand a wide range of temperatures, water conditions, and pH variations in their environment.
Guppy - Guppy aquaponics has the advantage of allowing you to grow herbs and veggies while also rearing vibrant, resilient fish. Based on experts' recommendations, Guppies prefer a temperature range of 72 to 78 °F (22°C - 26°C). Temperature fluctuations are not a problem for them. It's also crucial to keep the pH between 6.7 and 8.5.

Although there are three primary techniques for aquaponics, all of these follow general setups and components. These I will explain below.

Main Units

Aquaponics has two major parts - the hydroponic system where you grow your plants and the aquaculture system where fish are maintained.

The fish are housed in tanks, while the plants are grown hydroponically (without soil). Plants' roots hang down into a tub of water, but they sit in beds or rafts, depending on the technique you will adapt. When fish reside in tanks, their excrement accumulates in the water; these can kill them. What is harmful to fish is beneficial to plants since fish effluents contain nutrients they need to grow. So, with aquaponics, fish waste-laden water from the fish tanks is directed to tubs where the plants' roots dangle. Plants absorb the nutrients they require from the water, thereby cleaning it of pollutants for the fish. The cleaned water can then be pumped back into the fish tanks.

Secondary Units

These are the components that help recirculate the water throughout the system:

Aerator - This provides oxygen to the water, promoting robust health for both the fish and plants.
Pipes - These are usually PVC, and they transport the water in-between the main units, the hydroponic and aquaculture.
Lights - Could be natural or artificial, but these provide the radiant energy plants need for their food-making process.
Pump - Through this apparatus, the water can travel across the hydroponic system and fish tanks.

Biotic components

These describe the living organisms present in an aquaponics setup. There are three:

Aquatic animals - Freshwater fish are the most commonly used marine animal because they can tolerate crowding. Other animals utilized in aquaponics include prawns and, in some instances, saltwater fish. Fish from both cold and warm water can thrive in these environments. A common choice for aquaponics specialists is the tilapia fish due to its high resiliency against crowding and fluctuating water conditions.
Plants - The system can accommodate a variety of plant species. The fish population will decide the number of plants to grow. The plant's roots take the nutrients produced by the bacteria. Chinese cabbage, spinach, herbs, lettuce, and watercress are common plants grown in aquaponic systems.
Bacteria - These microorganisms are responsible for the process called nitrogen fixation. Here, the ammonia found in the animals' waste is converted into nitrite, which becomes nitrates. Plants make use of these nitrates for their development process.

How should I manage my aquaponics system?

Managing and maintaining an aquaponics setup can be tricky. However, once you have understood the essentials of aquaponics upkeeping, you will learn everything else quickly.

Feed your fish daily. Since fish are an integral part of your aquaponics, they should receive food at least once a day. Feeding them twice also works, one in the morning and one before sunset.
Check the systems' temperature. Some species are sensitive to their required temperature, so you need to check if the system's temperature is within the recommended range. If required, perform the necessary adjustments to ensure that your aquaponics system provides the ideal temperature for the species you are growing.
Be attentive to the pH level. The pH level determines the fish's health, the growth of germs in the system, and the plants' ability to absorb nutrients. As a result, the pH value of your aquaponics is crucial in determining whether or not your aquaponics works. It is advisable to check the pH level weekly. Most systems have an optimum pH of 6.8-7.0.
Inspect for the presence of insects. Conduct a weekly insect visual inspection of your setup. This practice is to ensure that any pest problems are addressed before they become hard to control. Remember, as well, that most insects prefer to stay in plant stems and under the leaves. It will be easier to locate insects in your system if you keep this tip in mind.

Whether you decide to adopt aquaponics technology for commercial or personal use, it is still vital to have a working knowledge of how it works. Aquaponics is a promising and sustainable approach. It will not only give you natural and nutritional food, but you are also contributing to the conservation of our planet for future generations. Using the information I have provided in this article, your aquaponics journey is off to a good start.

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