How To Use Aquaponics?
Aquaponics is a sustainable food production system that combines raising fish and plants together in one integrated system. It can be used in horticulture and commercial agriculture. It can also be used as an educational tool or by the home gardener who wants to reduce time spent maintaining the garden. The first step in designing your aquaponic system is understanding how it works.
This post will discuss steps you need to take when setting up your aquaponics system. This includes the basics of what you will need, what type of plants and fish to add, and when besides other requirements.
How Does Aquaponics Work?
In an aquaponics system, the plants in the grow bed are nurtured by fish waste coming from a nearby tank. The water from this tank is transported to the plant beds. Plants absorb nitrates and other essential nutrients necessary for their growth. In return, the plants clean and purify the water and release life-supporting oxygenated and clean water back to the fish residing in the fish tank.
Advantages of Aquaponics
Some of the most noticeable advantages of an aquaponics system include the following:
Faster growth: Plants grow three times faster with a more flavorful taste as they maintain their root systems without using up energy looking for water in the soil.
Health: Fish grown in an aquaponics system is pollution-free. This is the same for the vegetable and herb produce. You have control of what goes into your system.
Clean environment: One of the best ways to ensure a healthy, chemical-free diet is through aquaponics. Aquaponic systems are clean and sustainable while also being completely organic.
No more water wastage: Aquaponics uses 90% less water than traditional soil farming.
Types of Systems For Home Use and Commercial Use
Nutrient Film Technique
NFT systems are ideal for the commercial industry as they offer space efficiency and lower labour costs. This is best suited for leafy greens, but not large fruiting plants, as their root masses may clog channels. The plant roots get exposed to more air than water which leaves them vulnerable to temperature changes.
Media Beds
The media bed uses a container containing rock-based material like gravel or expanded clay (hydroton) which can support the roots of plants. It floods them with nutrient-rich water, so they have enough nutrients and oxygen. The media acts as both a mechanical filter for capturing waste products and as a biofilter since it breaks down these substances. Best suited for backyard gardeners as it does not require any engineering.
Deep Water Culture
A raft system is for those looking to grow their produce out of the water. Raft systems are an aquaponic way to get plant roots suspended in nutrient-rich and aerated water without the need for media. It is suitable for commercial production and is the most stable of the three. Commercial growers may require an aquaponics greenhouse for outdoor setups to save their system from harsh natural elements.
Things You Need For An Aquaponic System
To set up an aquaponics system, you would need the following:
Fish tank
Fish are just like pets. They need a lot of care and attention. Before adding them to a tank, you need to keep a few things in mind. First off, your tank needs to be big enough for the type of fish you want to raise. Remember, each species has its space requirements.
Then set up the tank just like you would a normal fish tank. Dechlorinate and cycle water for 4-6 weeks before adding any fish. This provides the bacterial population ample time to build up to help break down ammonia into nitrates needed by your plants. Lastly, don’t forget to add a pump to move water from the tank to the grow bed.
Build Media Bed
Build your media bed, also known as a flood table, on top of the fish tank. This increases plant growth area that would otherwise be too small if it were at ground level. The materials you may need are heavy-duty plastic trays and wooden pallet crates. Both should be built onto stands capable of supporting the weight. This is important so that they don’t fall into your aquarium.
After setting up your media bed, it is time to fill it with media. The best are clay pebbles; these are pH neutral and won’t affect the water quality as they absorb moisture well. For these reasons, many people choose them for their home aquaponics system. Beginners should keep the ratio of grow bed and fish tank as 1:1.
Add Fish
Now add fish species to the tank. Below are some species that work well in an aquaponics setup.
- Tilapia – easy to grow, does not require much care, and is disease-free
- Goldfish – produces too much waste, perfect for this kind of system
- Koi – Grows big and has high resale value
- Pacu – a fancy fish
- Ornamental fish – tetras, guppies, mollies, etc.
Stocking Density
How many fish should you add to your system? Ideally, it is 1 pound of fish per 5 – 7 gallons of tank water.
Add Plants
Apart from the fish and bacteria, another live ingredient in an aquaponics system is plants. Plants known to grow best are green leafy vegetables.
- Some plants you can grow quickly include kale, basil, lettuce, watercress, and mint.
- Other plants that you can sow and reap in this setup are beans, cauliflower, cabbage, cucumbers, tomatoes, squash, peas, strawberries, and peppers.
Oxygen Requirement
It is essential that there is sufficient oxygen in the system. You can accomplish this by using a separate aeration device and diverting a portion of water from the grow bed to the fish tank.
Maintenance
Maintaining an aquaponics system is easy. Feed your fish with a quality diet; it is essential to keep them healthy. One can use either flake food or frozen brine shrimp but beware of diseases you may introduce by adding live bait fish such as minnows and guppies.
Feeding Rate
Fish need a lot of care. Do not overfeed your fish and test the water levels frequently. The best practice is to feed them in about five minutes two or three times per day. And test pH level (should always be undetectable), ammonia levels (always zero) nitrites (low if plants are doing their job properly).
pH
An ideal pH level in an aquaponics system is 7. Fish require a pH of 6.5 to 8.0, and the plants need a pH of 5.0 to 7.0. For bacteria, the pH of 6.0 to 8.0. You may need to raise the pH as it will drop below 7.0 once the initial cycle has finished. To increase the pH, add calcium hydroxide or potassium carbonate in powdered form into your tank.
Furthermore, test the water pH every week or, if possible, 3-4 times a week.
When Is The Right Time To Add Fish To Your Aquaponics System?
Do not add fish until the system is cycled. For most aquaponists, cycled means that the water measurement has reached a level wherein you can add the fish. In colder regions, this process may take eight to ten weeks, whereas, in warmer regions, four weeks are sufficient. You can also boost cycling by inoculating the system, i.e., taking media samples from a healthy aquaponics system.
To confirm whether your system is cycled or not, check the following:
- Ammonia: > 2 ppm
- Nitrates: 160 ppm
- Nitrites: > 1 ppm (ideally > .5 ppm)
When Is The Right Time To Add Plants To Your Aquaponics System?
You should consider adding plants early on in the aquaponic cycling process. That way, your new plant will have time to establish before you introduce fish. You can also plant seedlings as these have well-established roots. However, they may show signs of stress at the beginning until cycling is complete. In such cases, add nutrients that are available in the form of organic supplements to boost growth and reduce stress.
What Not To Do When Using An Aquaponics System?
- Never use poor-quality water or tap water for your system. Check chlorine, pathogens, water alkalinity, and temperature for desired growth of fish and plants.
- Do not add sodium to your aquaponics system. It will build up and become harmful to the plants.
- Never use citric acid. Its antibacterial property will be detrimental to the bacteria in the biofilter.
- Always consider the fish to water ratio. Overcrowding fish tanks can lead to stunted growth or fish loss.
- Choose the right fish and plants. Growing non-native and non-seasonal plants will be of no use.
- Make sure your plants receive enough light. Use LED lights when you plan to grow plants indoors or in the shade.
- Do not use transparent fish tanks as there is a risk of algal growth in them. Use opaque tank materials such as PVC instead.
Summing Up
The benefits of aquaponics are clear. Not only does it provide a source of fresh, organic food for your family and friends, but you can also sell the excess to make some extra money. With the information provided in this article and a little research on how to get started with this sustainable practice in your own backyard or small space or commercial property, you will soon be enjoying all that aquaponics has to offer. All the best!
