The Aquaponics market is a growing market estimated to be worth over $870 million. The beauty of this aquaponic system is that the fish and the plants work in harmony to sustain each other naturally. You can create this neat, self-contained system cost-effectively and safely using Polyvinyl Chloride (PVC).
Here’s how to build a DIY aquaponic system with PVC:
- Build the wooden stand
- Assemble the PVC pipes
- Attach pipes to the frame
- Create holes in your pipes
- Drill holes in the cups
- Cover the pipe ends
- Fill the tank with water and connect the pump
- Fill the cups with planting medium
- Add plants into the growing medium
- Test the tank water pH and add ammonia
- Add fish into the tank
How to Construct an Aquaponic System With PVC
You can construct a PVC aquaponic system yourself by gathering suitable materials for the frame, pipes, tanks, and pump. You should also have a pH test kit to ensure the water is safe for your selected fish.
You can purchase most of your aquaponic system materials in your nearest hardware store, nursery, and local pet store.
The materials you’ll need are as follows:
- Four-inch (10 cm) diameter PVC pipes (You’ll save money if you get 10-20 feet (3-6 m) pipes and cut them yourself instead of getting already cut pipes. However, if you cannot transport long pipes, you can still get shorter pipes.)
- Four to six pieces of 4-inch (10 cm) diameter elbows
- Four to six pieces of 4-inch (10 cm) T connectors
- Fish tank
- Twenty-foot (6 m) aquarium tubing
- 4-way splitter. Get a 1-inch (2.5 cm) pipe
- An aquarium pump with sufficient power (This is to circulate the amount of water you need moving from the aquarium to the garden and back daily.)
- Plastic cups, which will provide space for your preferred potted plants
- Electrical tape
- Filter (you can also make your own filter)
- Hand drill
- Hole saw bit attachment (Make sure it’s slightly smaller than the PVC pipe.)
- A wooden stand
- Pieces of cloth
Once you’ve collected all the materials you’ll need, it’s time to start building.
Here are the steps to build your aquaponics system:
1. Build the Wooden Stand
Prepare the wooden stand and ensure that one side is shorter than the other. This way, the water will move using gravity once it’s pumped from the fish tank into the PVC pipes and back into the tank.
The use of gravity also allows the water to pour from the end of the pipe into the tank to create aeration in the tank, so your fish can breathe adequately. Place the wooden frame above the fish tanks, which should be large enough for the aquaponic system setup.
2. Assemble the PVC Pipes
Put the pipes together to test the water flow on the wooden frame. Depending on the size of your frame, you can connect two pipes to make a unit. So if you have four pieces, you’ll have two sets of connected pipes.
Use the elbows and connectors to put the pieces together. The electrical tape will tightly seal the joints to safeguard against water leakage.
3. Place the Pipes on the Wood Frame
How you place your PVC pipes on your wooden frame is very important. You need to ensure that the structure supports water flow from one end of the pipe to another. Without a proper flow, your system won’t function, so it’s best to do a check first.
Pour a little water on the upper opening and see if it’ll flow out through the opposite end without leaking through the seams. If the water is flowing uninterrupted, you have the frame and pipes set correctly.
4. Create Holes in the PVC Pipes
The number of 4-inch (10 cm) diameter pipes you use will determine the size of the aquaponics towers. If you want a large garden with various plants or even the same plant, you should use more pipes depending on your preference.
If you have 10-20 ft (3-6 m) pipes, you can cut them into 5 ft (1.5 m) pieces. Create 8-10 holes on each PVC piece. The holes can be 7 inches (18 cm) apart.
Next, mark the areas you want to drill. Use a hole saw bit attached to your drill to create perfect holes without damaging the PVC.
Using your drill, create a hole on the upper side of the PVC on the upper side of the frame. This perforation is the entry point for the pipe bringing water from the tank for the plants.
Drill a hole on the lower side on the other end of the pipe. Ensure the drilling point is positioned directly above the tank since this water will drip back into the tank.
If you have two sets of pipes, ensure both have the inlet and outlet points.
5. Drill Holes in the Cups
Put 5-6 plastic cups together and drill several holes at the bottom. Drilling multiple cups together will reduce damage. These holes will allow the plant roots to pass through as they grow and will also allow water into the growing medium, through which the plants will absorb the water.
6. Cover the Pipe Ends
It’s essential to properly cover the ends of your PVC pipes to reduce potential algae growth.
Algae are photosynthetic, just like plants, and they use carbon dioxide and sunlight to grow. They can produce pH swings that can negatively affect the health of your aquaponic system.
7. Fill the Tank With Water and Connect the Pump
Fill the tank with water. When using tap water, you need to aerate the tank to remove the chemicals usually found in the water. Chlorine is harmful to fish, so you need to ensure you get rid of it completely.
If your fish tank is small, you may need to bubble the water for at least three days. Larger fish tanks may need at least a week to rid the water of chlorine entirely.
Test the water’s pH. Ideally, it should be 6.5-7.5. Hard water tends to have a higher pH because of carbonates. You can choose to wait for the pH level to drop naturally or use an RO filter.
Nitrifying bacteria will naturally rid the water of carbonates and lower water pH over time. However, you can use a reverse osmosis (RO) filtration system if you wish to start immediately.
The RO system forces water through an invisible membrane, removing impurities and contaminants, such as pesticides, viruses, lead, carbonates, and many more. This process helps to lower the pH quickly so you can place the fish in the tank once you achieve the ideal pH.
8. Fill the Cups With Planting Medium
Fill the drilled planting cups with your preferred medium.
Popular aquaponics mediums commonly used include:
- Leca clay
- Lava rock
- Rock wool
- Water-absorbing crystals
- Rice hulls
- Growstone hydroponic substrate
When choosing the medium to use, you need to consider the system’s size and design. Ensure the rocks or pellets are of medium size. Growing mediums that are too large will delay growth.
9. Add Plants Into the Growing Medium
If you’re transferring crops grown in soil, you’ll need to wash off all the soil from the roots. Vermiculite is the best growing medium to use because it prevents cross-contamination of bacteria from the soil into the growing medium.
Ensure the plant is upright and has sufficient space to grow. Observe how the plants respond in the first few weeks. It’s not unusual for the plants to go into shock, especially when transferred from soil into the aquaponics system. Some may show signs of wilting, but they’ll bounce back.
However, if the plant isn’t showing signs of recovery after a few weeks, check if the roots are receiving water. If not, move the medium and reposition the plant deeper into the cup.
10. Test the Tank Water pH and Add Ammonia
Test the water in the tank again to confirm if the pH is at acceptable levels (6.5-7.5). Since the fish aren’t present to start the water cycle, you can add ammonia. The amount you add will depend on the size of the aquaponic system.
The ammonia will kickstart the nitrogen cycle while you prepare to introduce your fish.
11. Add Fish Into the Tank
Once you’ve set your aquaponic system and brought the tank water to the correct pH, you can add the fish. This process may take some time, depending on the size of your tank.
Be sure to acclimate your fish to the new tank water before placing them into the tank. Sudden changes in water quality or temperature can send a fish into shock.
This video is an illustration of how you can construct an aquaponic system with PVC:
What Is the Cost of Building an Aquaponic System With PVC?
The cost of building an aquaponic system can be overwhelming, especially if you’re switching from traditional farming, where the costs are relatively lower. The price will vary, depending on the materials and size of the system.
The cost of building an aquaponic system with PVC can start from $1500, depending on the size of your venture. Commercial aquaponics systems cost more to build than backyard aquaponic systems, which are much smaller. Using recycled materials like PVC, plant cups, and grow media can lower costs.
The pump and monitoring systems will increase your costs. However, they can last a long time, and since you’ll save on your food expenses, the aquaponic system will pay for itself over time. You can also find ways to cut costs, like buying a large container to act as a fish tank instead of going for customized tanks.
Mistakes to Avoid When Building an Aquaponics System
Building an aquaponics system can be intimidating, especially if this is your first attempt. You need to find the perfect way to make the fish tank environment safe and healthy for the fish and ensure your plants thrive.
These are common mistakes you should avoid when building an aquaponics system:
Using the Wrong Water for the Fish Tank
Rainwater and pH-neutral water are the best for aquaponics. If you have to use tap water, ensure you rid it of all impurities, especially chlorine, before putting fish in it.
Having Too Many Fish in Too Little Water
Ideally, you should have a 1-inch (2.5 cm) fish for every gallon (3.8 liters) of water. So, if you have a 10-gallon (38-liter) fish tank, you can have ten 1-inch (2.5 cm) fish or five 2-inch (5 cm) fish.
When you put plenty of fish in a small tank, you risk fish stress and fish diseases, which may stress your aquaponic system.
Using a Wrong Growing Medium
Factors such as size, weight, pH, texture, and durability matter when choosing the ideal growing medium for your aquaponic system. Mediums that are too small may clog your system, while those that are too big will have too many air spaces, affecting plant growth.
Using Harmful Chemicals to Lower Water pH
The fish tank’s pH is critical if the aquaponic system works optimally. Unfortunately, you may not have access to water with the correct pH (6.5-7.5 pH).
Chemicals like sulfuric acid and hydrochloric acid lower water pH, but they’re harmful. Instead, you should use less toxic options, like small quantities of vinegar and the RO filter system, to safely lower water pH.
Having the Wrong Plants and Fish
The plants and fish need to be compatible for a more successful aquaponic system. For example, if you’re going for tropical fish, you should choose plants that thrive during summer.
Ignoring Light in the Setup
The plants you grow using the aquaponics system still need light for photosynthesis. Unfortunately, many people forget this need when choosing the ideal location for the fish tank.
If you have no access to natural light, you can use LED grow lights. You can also use light meters to keep track of your plants.
Using Transparent Fish Tanks
The best fish tank for aquaponics is an opaque one. When you use a transparent fish tank, you’ll be creating the ideal environment for algae to grow. Algae will block the pipes and compromise your plants and fish.
If you prefer a clear fish tank, cover it and block out any light that may infiltrate the tank.
Failing to Feed the Fish Regularly
The plants in your aquaponic system rely on fish waste as fertilizer. Underfeeding the fish means the nitrate fertilizer levels will be low, affecting plant growth. An automatic fish feeder is a great choice for fish keepers who may be inclined to miss their fish feeds.
Adding Fish Too Early
Water pH that’s too low (acidic) will cause the mucus in the gills to thicken and inhibit oxygen absorption. If you leave your fish in this condition for too long, they’ll die.
Water that’s too alkaline (high pH) can limit the fish’s ability to release waste. It can also damage the skin, eyes, and gills.
Ultimately, water pH that’s too high or too low can lead to fish death.
Choosing the Best Fish for Aquaponics
When choosing your aquaponic system fish, you should know that not all fish waste is the same between fish types.
Your plants rely on fish waste to provide nutrients and food to grow. So when choosing the fish to use, you need to pair the right fish with the plants you intend to use for aquaponics.
Here are some things you need to consider:
The Type of Fish
Do you want edible or ornamental fish? If the fish is part of your food, you need to ensure suitable conditions. Edible fish are high maintenance and only thrive in specific water parameters.
Tilapia is one of the best species because it’s highly adaptable and reproduces quickly. Ornamental fish are more resistant to diseases, cheaper, and low maintenance.
The air temperature in your home is likely to impact the fish.
If you live in a high-temperature environment, you need to get fish species that prefer lukewarm water conditions, such as catfish, sunfish, and largemouth bass.
Fish species that need cold water to survive include trout. Large fish generally need more oxygen to survive, so cold water is suitable.
Sometimes, you may not have much choice when it comes to the type of fish to use. You may be limited to choosing locally available species, especially if you want to keep your costs low.
Local Fish Farming Laws
Before you venture into aquaponics, you need to find any laws or guidelines on aquaponics you need to follow.
Space Requirements for Different Fish Species
You need to consider the possibility that the fish you choose will grow in size. It may double or even triple in size in a few months, and the tank should have enough space to accommodate them.
For example, an adult channel catfish can weigh 40-50 lbs (18.1-22.7 kg). Such a fish will need a fish tank that’s at least 250 gallons (946.4 liters).
Fish have different breeding habits, and you should choose a fish species that suits your needs. For example, if you keep fish for food, you need a breed like Tilapia, which reproduces quickly and easily.
Unfortunately, if you have a small tank, this can cause you stocking issues. Having two tanks, one for breeding and another for young fish, will help reduce congestion and competition for space.
The Type of Diet
Did you know fish are classified according to their diet?
Herbivorous fish, such as the bristlenose catfishes, feed on algae, plants, and fruit. These fish have small stomachs, so they need to eat frequently. Omnivorous fish, such as freshwater fish, are excellent for aquaponics because they feed on meat and plants.
Aquaponics Growing Media
Although fish are critical in the aquaponics system, the growing media is just as important as it’ll contribute to the health of your plants.
The following are some popular options you can choose for your aquaponics.
Commonly known as LECA (Lightweight Expanded Clay Aggregate), expanded clay is an expensive but favorable grow media for all plants.
Although it’s lightweight, it provides adequate support for all kinds of plants. It has microscopic holes, allowing nitrifying bacteria into the aquaponics system and helping improve drainage. They’re also reusable, so you get value for money.
Growstones are made from recycled glass mixed with calcium carbonate. They’re then kiln-fired to create a lightweight, porous, and reusable medium for aquaponics. It retains moisture and aerates the roots of plants.
Lava rocks are a preferred growing media for aquaponics. They have a large surface area and are lightweight. They’re also pH neutral, porous, and have excellent drainage.
Unfortunately, the rocks have sharp edges that might cut your hands when handling them. They’re also likely to damage the plant’s roots.
Tips for Establishing Grow Media for Aquaponics
- Wash all other grow media, except LECA. Place them in a container and then pour vinegar over them. If they start bubbling, it has a high pH. The bubbles are a sign of vinegar reacting with limestone.
- Clean the media once or twice a year to prevent clogging of the aquaponics system. A clogged grow bed will raise the medium’s pH.
- Add two inches (5 cm) of dry growing media over wet media to prevent fungal growth.
When you decide to build an aquaponic system with PVC, you need to make sure the entire system works, not just for the fish but the plants as well. Choose the right growing media, water, and fish carefully. Care and attention to detail will ensure the entire aquaponic system will run seamlessly.