How to build a simple aquaponic system


Recently, more and more people have begun to take a great interest in aquaponic systems. Since I’m always looking for new and great ideas to improve my life, I also started to research these systems. But before we dive into the actual project, it’s a good idea to understand what exactly is an aquaponic system.

You would think that this idea is new, but the Aztec Indians raised plants on rafts on the surface of a lake in approximately 1,000 A.D. In modern times, the term aquaponics was introduced in 1970 when research on using plants as a natural filter began, most notably by Dr. James Rakocyat the University of the Virgin Islands.

The simplest way of describing this system is: the marriage of aquaculture (raising fish) and hydroponics (the soil-less growing of plants) that grows fish and plants together in one integrated system.



The fish waste provides an organic food source for the growing plants and the plants provide a natural filter for the water the fish live in. The third participants are the microbes (nitrifying bacteria) and composting red worms that thrive in the growing media. They do the job of converting the ammonia from the fish waste first into nitrites, then into nitrates and the solids into vermicompost that are food for the plants.

By combining both systems, aquaponics capitalizes on the benefits and eliminates the drawbacks of each.

Intrigued by the idea of being able to grow plants without much effort, I started to look into these systems. In my long and winding search for more information, I read books, researched the web and looked at videos to better understand the concept and see various ways of building it.

Finally, I decided to go with a flood and drain system.  It seems like the easiest system to set up and maintain and once it’s up and running it will run itself with very little need for intervention on my part.

The design is extremely easy to build and it won’t cost you an arm and a leg. And also it’s quite scalable, so if you want, you can build a bigger version of this. Here’s what you’ll need:

1. Tools:

1. Drill-Link-
2. 3/16″, 1/2″, 7/8″ Drill Bits-Link-
3. Hacksaw-Link-        
4. Pipe Cutter-Link- / -Link-
5. Razor Blade-Link-
6. Cutters-Link-
7. Thread Seal Tape-Link-

2. Materials:

1. 15 Gallon Plastic Bin (Grow Bed)-Link-        
2. 1/2″ Irrigation Tubing-Link-
3. 2 1/2″ Ball Valves-Link-
4. 3 1/2″ Barb Adapter-Link-
5. 1/2″ Flex Pipe Tee Insert-Link-
6. 1/2″ MNPT X Barb 90 Elbow-Link-
7. 2 #14 O-Rings-Link-
8. 2″ PVC Pipe 8 3/4″ long piece-Link-
9. 2″ PVC Cap-Link-
10. 1 1/4″ PVC Pipe 6 5/8″ long piece      -Link-
11. 1 1/4″ PVC Cap-Link-
12. 1/2″ PVC Pipe 5 5/8″ long piece-Link-
13. 1/2″ Male Adapter-Link-
14. 1/2″ Female Adapter (Electrical Conduit)-Link-
15. 2 1/2″ PVC Pipe 3″ long piece-Link-
16. 2 1/2′ 90 Degree Elbows-Link-
17. Pea Gravel (grow medium) -Link-      
18. 30 Gallon Plastic Tote (Fish Tank)     -Link-
19. Storage Shelves-Link-
20. 100 – 130 GPH Submersible Pump-Link-

Some of the lengths here are approximate because you have to cut to fit and fine tune the system. Also I had to use an electrical conduit fitting because normal pipe threads are tapered and you can’t screw them down all the way. I needed a tight fit to prevent leaks from the grow bed.

Step 1: The automatic siphon

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 Through my research I found that the most reliable way to make this system work was the use of a bell siphon. This consists of a 1/2″ diameter pipe (the upstand), the 1 1/4″ bell (a capped PVC pipe with crenellations cut in the bottom), and a gravel guard (everything I’ve read says you want to maintain about a 2:1 ratio in the pipe size).

In the first picture you have from left to right : the gravel guard, the bell pipe, the upstand and the drain pipe.

The upstand is inserted into the 1/2″ male adapter which passes through a hole in the bottom of the grow bed with an o-ring to prevent leaks from the grow bed. The female adapter attaches to the male adapter from the outside of the grow bed. The drainage assembly made up of the 2 90 degree elbows and 3″ long PVC pipes is then inserted into the adapter.

Step 2: The Water pump system

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The most vital part of the system is the pump. The pump I used is rated at 180 GPH, but since I’m pumping the water up about 2 feet that falls off somewhat. Even with the lower rate it is still too much for my purposes, but I put it to use.

First attach the pump to a small paver stone using zip ties to keep it pretty much where you put it in the fish tank. Then comes 1/2″ diameter irrigation tubing running from the motor to a barbed tee fitting. To this attach a small piece of irrigation tubing and a threaded adapter so you could screw on a ball valve.

This allows you to divert some of the water flow from the grow bed to the tank adding aeration to the water as well as water movement. To the other barb attach a longer section of irrigation tubing, a threaded adapter, a ball valve, another threaded adapter, more irrigation tubing and a 90 degree elbow fitting. This is for pumping the water into the grow bed. The ball valve is to control the flow of water into the grow bed which is very important for the proper functioning of the siphon.

Step 3: Filling it up

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Now for the fun part, seeing your hard work in action.

Put the system in its final location and make sure that is the place where you want it to be. Moving 25 gallons of water plus 14 gallons of rocks equals a hernia, so make sure that you pick the right place.

Fill the tank with water and add a water conditioner from the aquarium store to remove the chloramine.If your local water utility uses regular chlorine you can just leave the water out for a couple of days and it will evaporate out on its own. Position your water inlet for the grow bed (mine is held in place with a zip tie) and fill it with your chosen grow medium.

I used pea gravel, but you can choose something else, it’s entirely up to you.

Step 4: Testing the system


Before plugging in the pump make sure you read the instructions that come with it. Also remember that water and electricity don’t mix and can cause serious injuries.

The ball valve for your grow bed needs to be adjusted based on how your siphon is functioning. If the siphon doesn’t stop your water flow is too high, if your siphon doesn’t start your flow is too low. It takes a few cycles to get this adjusted properly. For mine it fills in 13 1/2 minutes and drains in 1 1/2 minutes.

Now is your opportunity to check for leaks and change anything that needs to be before you add fish.

Step 5: Adding the fish and the plants

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Put the plants in the grow bed. For the purpose of testing the system I used broccoli, but choose whatever you desire. After this add the fish. Depending on how large is the bin for your fish tank you can add different species. I used goldfish because they were extremely cheap and I also wanted to first try out the system before investing more into it.

Step 6: Testing the water


I would recommend that you test your water twice a day. You can pick up a water testing kit for aquariums from any pet store. Do it once in the morning and once in the evening. It’s also a very good idea to keep a log of all your results and keep notes about your observation regarding water quality, how the fish and the plants are doing and anything else you deem of importance.

I test my water twice a day with a kit for aquariums I picked up at the pet store. Once in the morning, and once in the evening. You can see in the picture I also keep a log of all my results and make notes about my observations such as water quality, how the fish are doing, and anything else of note.

Once you’re up and running all there is to do is feed the fish, test your water, check to make sure everything is running, and wait till you can harvest fresh veggies.

It took me about 2 h to build the whole project and I spend 15 min a day on maintenance.

As I mentioned, the design is scalable and can suffer modifications to it. I used the basics of how the system works in order to build this project. You don’t need to get all high-tech or complicated to make your very own aquaponic system.

To help you get a better notion of the components and different options for each, below you will find a list that will help you in your quest.

  • Fish Tank:You can use a traditional glass fish tank though that would be a bit more expensive. As an alternative, it’s very common for aquaponic gardeners to use a large barrel or a stock tank.
  • Flood Table: This will be used as a grow bed for growing your plants on. The bigger the size, the more plants you can grow, but you also have to factor in whether your tank can hold enough fish to provide sufficient nutrients for the amount of plants you want to grow. Click here to check out various effective grow beds.
  • Support: You need to support the grow bed with a sturdy foundation. Using sets of concrete blocks and lumber will do well. Alternatively, you can get pre-made frames but once again, they tend to cost a bit more unless you pick up a second hand bargain. Click here to check out a variety of sturdy grow bed stands.
  • Water Pump: When choosing a water pump, make sure that you get a reliable and trustworthy brand. Magnetic drive (mag-drive) pumps are best because the motor has its own separate compartment which is sealed off and it should never leak any oil into the fish tank. Click here to check out highly effective water pumps. 
  • Grow Bed Media: Gravel is cheap but depending on the rock used, it can affect pH levels in the water. You can also use clay pellets which are pH neutral and holds moisture well. Click here to check out suitable grow media.





How else would you build an aquaponic system? Share your thoughts in the comments section below.


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