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Recirculating Cultivation Systems – Hydroponics vs Aquaponics, Which Is the Best Approach?

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Hydro recirculating cultivation systems are incredibly efficient ways to grow plants. Several approaches can be taken, but the two most prominent are hydroponics and aquaponics. Both systems are incredibly efficient ways to grow but which is the best approach?

There are many different forms of hydroponics from fully hydro-based systems through to semi- hydroponic systems where the hydro system is combined with another growing medium. Aquaponics is itself a branch of hydroponics but is fundamentally different in how nutrients are added and managed by the system

Hydroponics and aquaponics are systems that use nutrient-rich water to grow plants. The difference between the two is how nutrients are introduced and managed by the processes. With hydroponics, the plants grow in a nutrient solution added and managed, whereas, with aquaponics, a natural ecosystem is created where fish waste is converted into nutrients and absorbed by the plants. 

Why Use Recirculating Cultivation Systems

Recirculating Cultivation Systems - Hydroponics vs Aquaponics

Recirculating cultivation systems, like aquaponics and hydroponics, are becoming increasingly popular for a number of reasons. They are productive, produce little waste, and require minimal inputs after the systems are established. They are also versatile and can be scaled up or down to meet the needs of the grower.

One of the most important benefits is the efficient way to produce food with a small footprint. The systems can be designed to meet the specific needs of the growers, whether that is production volume, type of crop, or climate. They can be used to grow a wide variety of crops, including leafy greens, herbs, tomatoes, and even fish.

Recirculating systems are also very water efficient. In a hydroponic system, the water is recirculated and only lost to evaporation and transpiration. In an aquaponic system, the water is recirculated and the waste from the fish is used to fertilize the plants. This closed-loop system results in very little water waste.

The water and fertilizer savings are substantial with between 90-95% reduction in water usage and up to 99% reduction in fertilization with aquaponic systems.

Recirculating Cultivation Systems

Parameters %Nutrient solution systemAquaponics
Water saving90%85-90%
Fertilizer saving85%85-99%
Productivity increase250%150%
Water Productivity3500%1600%
Hydroponics, Aquaponic as Compared
with Conventional Farming [1]

These systems can also be very space efficient. They can be designed to fit into small spaces, like a corner of a room or a balcony. They can also be designed to maximize production in a small area. For example, vertical systems can be used to grow more crops in a smaller footprint.

In terms of yield recirculating cultivation systems uses just around 5 percent of the water and a tiny proportion of the land that conventional farming does to produce the same quantity of food.

Hydroponics System 

Hydroponics is a method of growing plants where the nutrients are provided through the water rather than soil. The system is flexible in that it can be a pure hydro system such as the nutrient film technique (NFT), or a semi-hydroponic system where it can be combined with another growing medium like coco noir, perlite, LECA. However here we are concentrating on pure hydro recirculating cultivation systems

Chemical nutrients are added to the water creating a hydro nutrient solution, which is then either added a reservoir supplying a cultivation network. Within this channel network, the nutrient solution is circulated returning to the reservoir and then is recycled through the system with careful monitoring and topping up of the water’s nutrient levels.

Aquaponics Systems  

Aquaponics Systems  

Whilst aquaponics is a hydroponic method as it entails the growing of plants in a water-based environment, it is different in that it uses living aquatic animals as an integral part of the process. This use of aquatic animals is so fundamental and from hydroponic recirculating cultivation systems that it is considered a separate branch in the field of hydroponics.

The term “aquaponics” is a combination of the words “aquaculture” and “hydroponics.” Aquaculture is the practice of raising fish in a controlled environment, and hydroponics is the method of growing plants without soil. Aquaponics takes the best of both worlds and combines them into one efficient system

Aquaponics is a method of food production that combines raising aquatic animals with growing plants in water. This system can be used to produce both fish and vegetables, using far less land and water than traditional agriculture. Aquaponics is a sustainable way to produce food, as it recycles water and nutrients, and doesn’t require the use of harmful pesticides or herbicides.

How Do Recirculating Cultivation Systems Work?

Both systems work in much the same way and you can make the systems as straightforward or as intricate as you like; for example, you could use just one channel, or you could have multiple channels that are stacked on top of one another or laid out in any configuration that does not impede the flow of the nutrient solution.

To successfully cultivate plants using the recirculating cultivation method, a  nutrient solution is required. The lower part of a plant’s roots sits directly in the solution that flows through the channels, in contrast to traditional aeroponic systems in which the roots are suspended in the air. This solution transports the nutrients to the plant’s root systems, which then have the opportunity to draw them up through capillary action and directly absorb the nutrients.

The solution is initially added to a reservoir for hydroponics while with aquaponics the nutrients in the reservoir (fish tank) are derived from fish culture. Depending on the design, either a water pump or gravity helps it move the nutrient solution through the channels. After that, it travels back to the reservoir, where it is recycled and is then sent back through the system in a continuous flow.

Because the plants in a recirculating cultivation system are grown in holes drilled into the top of each of the growing channels, the roots of the plants are able to dangle above the nutrient solution that is contained within the chamber, while the plant’s crown remains above the solution.

Main Differences Between Hydroponic and Aquaponic Systems

Despite both being hydro-based systems, there are considerable and significant differences between the two systems.

Nutrient Solution

The obvious difference between the two systems is that with aquaponics your nutrients are being managed through the conversion of fish waste into fertilizer. At the same time, with aquaponics, you are cultivating both plants and fish. In this respect, you are providing wholely organic nutrients to the plants

With hydroponics, on the other hand, nutrient management is don’t through the addition of chemical nutrients to create a hydro nutrient solution in the reservoir. There is no aquatic husbandry required as you are only cultivating plants.  

Space Requirements

Hydroponic systems can be scaled to any size, so you can use as little or as much space as you have available. In general, a hydroponic system requires less space than an aquaponic system because you don’t need to accommodate a fish bin. You can also eliminate the need for a growing bed and just have the plants in pots.

Whilst this can save a significant amount of space, aquaponics built on top of domestic fish tanks, although small scale, can be used to create a feature inside your home.

Setup and Operating Costs

One of the main reasons that aquaponics is more expensive than hydroponics is that it requires more equipment. Aquaponics systems need an air pump to aerate the water, and they also need a filtration system to remove solid waste from the water. These components add to the initial cost of setting up an aquaponics system. In addition, aquaponics systems need to be stocked with fish. The cost of fish varies depending on the type of fish you choose to grow.

Another reason that aquaponics systems are more expensive to operate is that they require more electricity than hydroponics systems. Aquaponics systems need to be aerated constantly in order to keep the water oxygenated for the fish. This means that aquaponics systems use more electricity than hydroponics systems.

In addition, aquaponics systems require more water than hydroponics systems. Aquaponics systems need to be stocked with fish, and the fish need to be fed. This means that more water is used in aquaponics, with additional running expenses in terms of electricity costs and fish feed than with hydroponics. However, some of these costs can be offset by selling cultivated fish at the end of each growing season

Start-Up Speeds

establishment speeds

Aquaponics systems are slower to get up and functional because of the fish. At a minimum, it takes a month to develop the nitrifying bacteria needed to break down the fish waste; most systems can take upwards of 3 months to stabilize the environment enough to introduce plants.

In order to set up an aquaponics system, you need to first cycle the tank to establish a colony of nitrifying bacteria. This process can take anywhere from one to three months, depending on the size of the tank and the number of fish.

Benefits of an Aquaponic System

The differences so far discussed suggest that aquaponics is a more complex, more expensive, and slower system than hydroponics. Whilst in many senses this is true they are in practice relatively minor and there are also a number of important benefits in building and using an aquaponic method.

Saving on The Cost of Fertilizers

The most obvious benefit is the self-propagation of fertilizer. This means aquaponic systems are a great way to produce food without the need for extra fertilizer, as opposed to hydroponics where fertilizers are required.

The fish in the system provides the waste that is broken down by bacteria into fertilizing compounds. This means that the plants in the system get all the nutrients they need without you having to add anything extra.

Mimicking the Natural Ecosystem

In a natural ecosystem, plants and animals are constantly interacting with each other. The waste from the animals is used as food for the plants and the plants provide shelter and oxygen for the animals. This close relationship between plants and animals is what makes an ecosystem so efficient. Aquaponics mimics this relationship and as a result, is a very efficient way of growing plants.

In aquaponics, the fish produce the waste that is converted into a natural fertilizer for the plants. The plants then filter the water, which is returned to the fish. Because of this balance, aquaponics is simpler to keep after the setup process than a hydroponic system, although constant monitoring is required.

No Routine Water Disposal Required

One of the most important aspects of keeping an aquaponics system healthy is managing the chemical water balance. Unlike hydroponic systems, which rely on you to regularly cycle in new water to prevent chemical buildup, aquaponics systems are self-regulating. This means that you do not need to worry about disposing of old water or adding new water to the system.

The chemical buildup in hydroponic systems is a result of the added fertilizers that you must supplement in order to feed the plants. This requires you to have a planned disposal method to prevent environmental damage. With an aquaponics system, this can be avoided

Issues To Consider With Aquaponics 

It is clear that aquaponics is more complex than hydroponic systems and as such there are several issues that you need to watch out for. If you feel able you will find that it is a rewarding system for growing plants.

Understanding the Water Chemistry

Water chemistry is one of the most important aspects of running a successful aquaponics system, but it can also be one of the most difficult to get right especially when aquatic animals are involved.

Fish produce waste that has to be filtered out by the plants in the system, and if the water chemistry is off, it can cause problems for both the fish and the plants. Too much waste in the water can lead to ammonia and nitrite poisoning in the fish, while not enough waste can stunt the growth of the plants.

However, getting the water chemistry right is a delicate balancing act, and it’s important to do your research before adding fish to your system. You need to make sure that the water is at the correct pH and temperature.

It’s also important to have a plan for disposing of the waste that the fish produce. Aquaponics systems rely on the beneficial bacteria in the system to break down the fish waste into nitrates, which the plants can then use as fertilizer. If the waste builds up too much, it can throw off the chemical balance of the system and lead to problems.

The key to success is to start with a well-planned system and to be prepared to adjust the water chemistry as needed. With a little patience and trial and error, you can create a thriving aquaponics system that produces healthy fish and bountiful crops.

Oxygen Levels

In addition to the basic chemistry, you need to make sure that there is enough dissolved oxygen in the water for the fish to breathe. As fish require a substantial amount of oxygen to be present in the water you will need to monitor the dissolved oxygen levels and make sure they are adequate for the fish’s survival.

The Wrong Fish Choice

wrong fish choice

There are a few things you need to consider when choosing fish for your aquaponics systems, such as the water temperature and the type of plants you want to grow. If you select the wrong fish, it can have a negative impact on the growth of your plants. This is because each type of fish has different needs in terms of temperature and pH levels. If the fish and plants you have selected do not have similar needs, it is likely that one or both will not thrive. This can lead to stunted growth or even death.

To avoid this, it is important to carefully consider the water conditions and temperature you can provide before selecting your fish. It is also a good idea to choose fish that are native to your area, as they will be better adapted to the conditions in your aquaponics system.

Hydroponics vs Aquaponics: which should YOU choose?

Choosing one love the other will depend on a number of factors and will depend on what you are looking for. once set up aquaponics, in terms of efficiency, is the best option

Aquaponics is a great option for those who are looking for an environmentally friendly way to cultivate various types of plants and fish. It is a more natural and sustainable way to produce, and it has a lower carbon footprint than other methods of food production.

However, aquaponics is a more expensive way to cultivate than hydroponics. So, if you are looking for the most environmentally friendly way to produce plants, leafy greens, and fresh fish, aquaponics is the better option.

If you want faster results and are concerned about the management of aquaponic systems then hydroponics is the better option. It is a little more efficient in terms of water and power usage and environment stabilization is much faster meaning you will be able to harvest earlier. However, with established systems plant growth rates are similar.

Summary

Both are flexible systems designed in numerous different ways and both have many advantages over traditional soil gardening. You could even set up a small version of either system in your front room to grow leafy vegetables if you didn’t have access to outdoor space.

The main difference between aquaponics and hydroponics is that it uses fish waste to fertilize the plants, while hydroponics uses chemical fertilizers. If you are after the most environmentally friendly system which is fully organic then aquaponics is the better option. Whereas if you want efficiency and less complexity hydroponics is better.

With either system, it is crucial to maintain and monitor them properly or you will experience low yield, root rot, and the growth of algae.

Notes:

  1. American Scientific Research Journal for Engineering, Technology, and Sciences, Ali AlShrouf: Hydroponics, Aeroponic, and Aquaponic as Compared with Conventional Farming