Types of Aquaponics Systems
Aquaponics is a growing farming system that combines aquaculture, or fish farming, and hydroponics, the method of growing plants without soil. The two systems work together to create a closed-loop that produces food without depleting any resources from the environment.
Aquaponics is a sustainable food production system in which the waste from the fish tanks provides nutrients for the plants, and in return, oxygen from the plants helps fish thrive. Aquaponics can be done on an individual scale or as part of a commercial operation.
This article will provide information on some common types of systems to help you choose which one would be best for your needs. Also included will be an overview of how each type works and its advantages!
There are five types of aquaponics systems, namely:
- Media-Based
- Nutrient Film Technique
- Deepwater Culture
- Vertical Aquaponics System
- Hybrid Aquaponics System
We will discuss each one in more detail to help you decide which one would work best for your situation!
Media-Based
Media-based aquaponics is a type of farming where plants grow on the surface, and their roots are held down in a suitable medium. A little pond for fish provides nutrients through its waste, which helps plants to grow.
How Does It Work?
The media-based aquaponics system has a grow bed with media filled in it. The media could be lava rock, gravel, or clay pebbles. The water from the fish tank is moved into this area, where it’s accessed by plants. Plants are able to absorb nutrients more efficiently in these porous areas that hold onto water for optimum nutrient uptake while filtering out material that could harm the fish.
The grow bed is like a filter and also the perfect place for bacteria to live. It’s where plants can get their best shot of minerals, too. The water is clean and also free of solids when it leaves the grow beds, enters the sump tank, and finally into the aquaponics fish tank. This raises the water level in the fish tank, and the overflowing water moves to the water tank. And the cycle continues.
One of the types of a media-based aquaponics system is flood and drain. In this, flooding and draining of the grow beds happens when it reaches a saturation point. A bell siphon drains water from the grow bed. This also brings oxygen back into the grow beds, which makes sure that the plants have all the nutrients they need in the absence of fertilizers.
Best plants to grow in a media-based aquaponics system:
- Plants with low nutrient demand: mint, basil, lettuce, parsley, chives, coriander, watercress, and legumes.
- Plants with medium nutrient demand: kale, cabbage, cauliflower, onions, taro, carrots, and broccoli.
- Plants with high nutrient demand: eggplants, tomatoes, strawberries, cucumbers, and peppers.
Advantages of a media-based aquaponics system
- Simple and cost-efficient
- Low maintenance
- It suits all types of plants, from large fruiting to small leafy
- Perfect for home gardeners and hobbyists
Nutrient Film Technique
The nutrient film technique (NFT) is an aquaponic technique where water flows around roots, like on the surface of a stream. It is interesting to note that the plant growth rate with NFT aquaponics is at par with the NFT hydroponics system.
How Does It Work?
The NFT filtration system works by pumping or flowing freshwater through mechanical filters before they enter into biofilters. Some amount of water moves directly into the fish tank, and the remaining is distributed through the pipes. Water flows by gravity down the grow pipes where aquaponics plants are growing.
After they exit the grow pipes, water returns to the sump or the biofilter. It then moves back to the fish tank, or the grow pipes. Water entering the aquaponics fish tank makes it overflow, moving the water into the exit pipes and then into the mechanical filter. And this completes the cycle.
The plants grow in the several holes on top of the grow pipes. This is where they start developing the root systems after imbibing the nutrient-rich water. A shallow film of liquid at the bottom ensures that roots receive plenty of oxygen as well.
Biological and mechanical filtration
In the absence of sufficient area for microbial growth, mechanical and biological filters are required to catch the solid water. In addition, the biofilters are for nitrification. The biofilter is nothing but a barrel or a tank for the heavily aerated porous medium and should be placed after the aquaponics fish tank.
Best plants to grow in NFT
Plants that need less care and have shallow roots are perfect for the NFT system. These include chard, lettuce, mint, basil, sage, mint, mustard.
Advantages of Nutrient Film Technique
- Uninterrupted supply of water, nutrients, and oxygen
- Easy to operate
- Space efficient
- Lower labour costs
Raft System
Also known as the deep water culture method, the raft system of aquaponics is one of the most efficient aquaponics techniques. It is generally implemented in large-scale or commercial aquaponics because it can produce large quantities of food efficiently and quickly.
How Does It Work?
In a raft system, the nutrient-rich water circulates through long canals (the rafts are 20 cm deep) while plants grow on raft boards (made of foam board or polystyrene). Net cups support them with holes drilled to fit them, depending on what vegetables you want to grow. The roots of these planks hang in oxygenated and nutrient-rich water, where they absorb nutrients to grow quickly.
The water is filtered and flows continuously via the fish tank, then to a raft where plants are growing, and finally returns to the fish tank. Usually, the raft tank is different from the fish tank. The useful bacteria live in the raft tank, in the biofilter, and all through the system.
It is vital for a successful system that you design it well, so make sure your selection of plants is just right. During harvest, remove the entire aquaponics plant and the dead leaves and roots from the canal. Clean the raft but do not leave it to dry, or else the nitrifying bacteria will also die.
Best plants to grow in the raft system
Small and lightweight plants such as lettuce, leafy greens, kale, basil, card, and collard greens are suitable for the raft system.
Advantages of the raft aquaponics system
- Simple and economical
- Maintenance is easy
- Ideal for hobbyists, home gardeners, and commercial farmers
- Easy plant harvest
- Gives higher produce
Vertical Aquaponics System
A vertical aquaponic system is an excellent way to grow plants without soil in columns above a fish tank. This gardening and raising fish method has become popular among aquaponic gardeners because it is water-efficient and space-saving. In addition, it allows growers to produce twice the amount of crops compared to the media-based systems having the same area.
How Does It Work?
Vertical aquaponics is a system of farming that grows plants in long narrow channels. It utilizes the NFT (Nutrient Film Technique) aquaponics method. The difference lies in the setup. While in the NFT system, the grow channels are defined horizontally, in vertical aquaponics, these are designed vertically.
Best plants to grow in the vertical aquaponics system
Basil, parsley, kale, strawberries, spinach, lettuce grow well in vertical aquaponic systems besides many more.
Advantages of the vertical aquaponic system
- Small space required.
- Help grow more plants than the horizontal aquaponics
- Water recycling ensures less water is used
- No pesticides are used, so plants grow organically
- It can be customized easily
- Cost-efficient and perfect for urban farming
- Highly flexible (works outdoors, indoors with lighting, and in a greenhouse)
Hybrid Aquaponics System
A hybrid aquaponics system is a perfect combination of two or more systems into one. You can find many approaches to the hybrid system, and all are equally effective depending on your needs. Some home growers use this type for its efficiency, while commercial ones prefer it because they need space-saving measures in their growing process.
How Does It Work?
Here is an example of a hydroponic system with all three systems in one aquaponics system. The water moves from the fish tank to the vertical towers and then to the media beds and drains into the DWC system. Finally, it moves back to the aquaponics fish tank. This completes one cycle.
These aquaponics hybrid urban growing systems can be scaled to size and also replicated as per the need. They may even operate off the grid, too, if you modify them enough.
Best plants to grow in a hybrid aquaponics system:
You can grow all green leafy plants and herbs in the hybrid aquaponics system.
Advantages of the hybrid aquaponics system
- The productivity is high
- It also has high flexibility for growing plants
Wrapping Up
Aquaponics is an interesting and sustainable way to grow your food. There are several types of aquaponic systems, but you can always start with a simple system that does not require much time or money. Further, the best type for your needs will depend on factors like how much space is available in your backyard, what kind of fish waste you want to raise, etc.
Regardless of which particular system suits your needs, we hope this article helps you start thinking about some options. Now it is just a matter of doing some research before buying and installing a suitable aquaponics system. All the best!
