20-gallon Aquaponics System




Introduction: 20-gallon Aquaponics System

This is a smaller Aquaponic system, intended to be used in a classroom for educational use.

Step 1: Gather Materials

Before you even start constructing your system you need to be aware of all the materials you have to work with. Our group was given a set of materials (see attached document for prices) that consisted of:

5- 5 Gallon Buckets

3/4" PVC 90 degree elbow (3 pack)

3/4" PVC 45 degree elbow (3 pack)

3/4" PVC Pipe 3 feet

3" PVC Pipe 3 feet

3/8" Clear Vinyl Tubing

LENOX 1-1/4

1.25" Hole Saw

80 GPH Fountain Pump

PVC Cement and Primer

GROW!T Expanded Clay Pebbles

API Freshwater Master Test Kit

API Tapwater Conditioner 16oz Bottle

Purina AquaMax Fingerling Starter 300 Sinking Pellet 3lbs

Fish Feeder

Tubing Restrictor Clamp

Radish Seeds
Indoor Mechanical Timer

TaoTronics LED Grow Lightbulb

3/4" Uniseal Flexible Tank Adapter (5 pack)

25 ct aquarium bio balls

Step 2: Brainstorm Ideas

Our group remembered the constraints and started trying to plan accordingly. We knew we had 5 buckets to work with and we knew we needed a least 4 different compartments. We thought about what are system needed to focus on the most and that was the fish, the plants, and the filtration. We knew we needed exactly one bucket for the plants and two buckets for the filtration. Since we knew each of the tilapia fries needed 3 gallons we thought we might use 2 buckets to house them. With 2 five-gallon buckets, we felt we could appropriately house 4 fish. We thought we could also use the extra bucket to separate the bio balls and swirl filter.

Step 3: Create a Plan

After getting our actual materials that we were working with our designed changed a little. We also decided to consolidate the mesh filter and bio balls so that we could have an empty bucket for adding chemicals and monitoring the water. Our final system had water flowing from an elevated grow tray held up by an upside-support bucket. the bottom 3 buckets would be for the fish, the filtration bucket, and the monitored bucket.

Step 4: Begin Construction of the Bucket Portion

We first started by taking the handles off the buckets and then by cleaning some of the trim from the buckets. We removed the trim by slicing it off by combining a wood burner and an Exacto blade. We then lined up and marked the buckets by where we wanted to connect them. We used a string and a marker to guide an even cut around the grow tray bucket to make it shorter. Lastly we lined up our buckets for how the water would flow.

Step 5: Add in Plumbing

In all the buckets, we inserted the uni-seals with an expanding lip design, to create a complete seal all the way around, as the pipes go through.

Step 6: Add Water to Test System

We began by adding water to the grow tank, testing the bottom seal to ensure that nothing leaked. Then as the seal was tested, we put water into the rest of the system to ensure the seals were tight and no water would flow outside.

Step 7: Began Working on Grow Tray

We cut the 5 gallon bucket 5.5 inches from the bottom all the way around. We then attached the Media filter pipe an inch and a half from the edge. The media pipe is there to prevent any of the grow media from getting into our bell siphon area. We did not glue the media pipe down, however we should have as we encountered a few issues with media getting into the pipe as we got it all settled in. The media pipe had lots of holes drilled into it, to allow ample water flow, but it's important to make sure the holes you drill are smaller than the media that you place into the grow tray.

Step 8: Construct Bell Siphon

In order to create the bell siphon, we used a 3 inch pipe (black) and 1 inch pipe (white) to create the suction. In order to see the process in action, we created an acrylic covering, that also functioned as the seal in order to get the Bell Siphon to activate. There were multiple holes drilled into the bottom two inches of the bell siphon to allow water to pass through, as well as a single extremely small hole, in case the system failed, it will drain out so the plants will not drown. We originally ran into some siphoning issues, getting it to activate and to stop, so we 3D printed a small funnel like piece that decreased the hole's radius to just half an inch in order to create more pressure inside the pipe, allowing for easier flow.

Step 9: Adjust Bell Siphon for System

While constructing our Bell Siphon, and after dozens of tests, we noticed an issue that there was too much pressure, so the siphon wouldn't "break", or reset to clear the siphon and begin filling it up again. To combat this, we drilled a hole at the top and attached an air tight tube, and ran it along the base of the pipe to the hole line near the bottom. This allows for more opportunities for air to enter the system and "break" the siphon. We experimented with adding cuts on the sides, however this just added air into the siphon system, but not enough to break the siphon. It added enough air to slow it down, but not enough to stop it.

Step 10: Prep System for Fish

Add seeds for plants and condition the water

Step 11: Add Fish

Add 2-3 fish depending on breed and size. There should be 3 gallons of water per inch of fish for the Tilapia fish we used therefore we only put two fish in our fish tank bucket.

After adding the fish we ended up needing modifications to the system to prevent the fish from jumping out. This will be explained further later on.

Step 12: Observe and Monitor System

Keeping the system clean and making sure that roots and growth medium are not interfering with the bell siphon are key to making sure the system functions properly.

As we monitored our system and observed it we were constantly having to clean the roots and pebbles out of the bell siphoned as well as using a siphon vacuum aquarium cleaner to help when we did a water change.

Step 13: Make Adjustments

The major adjustment we had to make to our system was to add some type of cover to the fish tank part of our system to prevent the Tilapia from jumping out. We had one fish that insisted on trying to get out of the tank so we decided to put a wire cover over it and this was successful in preventing the fish from being able to get out.

Another minor adjustment was making sure the pipe that goes into the fish tank to fill it was tight so that it was not falling out and making sure there was something to filter the water coming out of the grow bed into the fish tank to prevent excess dirt particles from the growth medium from getting into the fish tank.

Step 14: Watch Your Plants and Fish Grow!

The final part of the aquaponics system was to monitor it and was the radishes and fish grow. Over a few weeks we had about 5-7 radishes grow and our 2 fish grew a decent amount given the amount of space they have and the conditions they are in.

For a beginners system this was an extremely successful system and we learned a lot while we went through the process of building, troubleshooting, adjusting, and monitoring our system.

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    5 Discussions

    Eric T
    Eric T

    3 years ago

    Nice! Whare do you order the tilapia?


    Reply 3 years ago

    We actually got our tilapia donated from a local fish farm, but we hear there are actually lots of websites to order them from.

    Eric T
    Eric T

    Reply 3 years ago

    Thank you


    3 years ago

    Very enterprising post, as good usage of things are being made. Since some funds need to be keep intact for cleaning the property from janitorial services.


    3 years ago

    Looks like a good setup, I'm glad the fish and plants did so well!