What is Aquaponics and How to Build a Micro Aquaponics System for about $50.00

What is Aquaponics

micro aquaponics seed starter

One of our micro aquaponic systems on an apartment balcony

Aquaponics is the combination of 2 things:

  1. Aqua Culture: The practice of Raising Fish
  2. Hydroponics: The practice of Growing Plants using water, chemicals and a non soil medium like gravel
Aqua Culture is pretty self explanatory. But let’s talk more about Hydroponics.

What is Hydroponics

Hydroponics is a system designed to grow plants indoors. Basically you take a container and fill it with a non-soil growing medium such as gravel, and you plant plants into it.
Some people use clay balls called Hydroton. The reason to avoid soil is so that you can avoid soil-born diseases. Another reason is that soil you are keeping in a container indoors is not very fertile after a while since there are no worms, rainwater, decomposition, etc., that you would get outside in nature.
A second container is also set up that is filled with water.  To this water, the hydroponics grower adds all of the chemicals in liquid form that plants love such as Nitrogen, Potassium, Phosphorus and the like.
Now for the tricky part.  The two containers are connected together usually with pumps and hoses so that the water/fertilizer solution is pumped into the gravel and then allowed to drain back out into the water container.  The 2 containers now form a system in which fertilized water is continuously recirculated through the gravel.  Every so often, more liquid fertilizer is added to the water since the plants slowly consume it.
Sound complicated?  It is. But it works. Plants are super-fed exactly what they need when they need it and they thrive. Of course you also have to put strong lights over the plants since the plants are inside.  Sound expensive?  It is.  Here is a bad drawing of what a hydroponics system looks like.  The green things are the plants…

The water is pumped up to the gravel bed and drains back down into the liquid container to be pumped up again over and over

Back to Aquaponics

Aquaponics is the combination of Aquaculture and Hydroponics.  The way it works is that the water container is replaced by an aquarium of fish.  Everything else is pretty much the same.  But when you replace the water/fertilizer container with a living fish aquarium, a lot of good things result such as the following:

  • There is no longer a need to add any chemicals or fertilizers because the yucky fish water is the stuff that feeds the plants and they love it!
  • When the water filters through the gravel and plant roots, it gets cleaned for the fish!
  • So the plants keep the fish alive and the fish keep the plants alive.  It is a closed, living system.  Well, almost a closed system: you do have to feed the fish as you normally would in an aquarium
  • The fish require no additional filtration and also do not require an air bubbler.
  • Once up and running, there is very little monitoring or maintenance needed.

What can Aquaponics Do for You

Imagine that you moved the system outside, made the grow bed larger and thinner, and set up a huge water container like those used to water cattle.  This system could grow Catfish or Tilapia.  In this bad drawing the grey things are delicious Tilapia

Aquaponics system drawing

I’m not suggesting you do this in your backyard, but people do.  The plants in this system are vegetables, so you are raising meat and produce together. The black device is a standard pond pump.

On a much smaller scale people are experimenting with Micro Aquaponics.  With Micro Aquaponics, you take a small aquarium and a small grow bed and use it for growing seedlings to transplant into the garden.  They make terrific seed starters and cuttings propagators.  The fish can be goldfish or other standard fish from the pet store.  Take a look at one I built and put on my patio.

micro aquaponics system

My Micro Aquaponics System on my Patio growing things I planted from seed

I made it for about $50.  The water jug is there because every so often I had to fill up the 10 gallon aquarium with water from my rain barrel due to evaporation and expiration from the plants.  I had about 5 fish powering the whole thing and the only input was tropical fish flakes, a pinch per day.  you can take it apart for storage in the fall or move it inside.

Indoor micro aquaponics system seed starter

One year I moved my Micro Aquaponics system inside and put it under a shop light with a couple of CFL bulbs.  It lasted all winter for growing micro greens

How To Build a Micro Aquaponics System

Well there are tons of plans and designs on the Internet that you can check out.  I won’t go into full detail on mine but basically here’s what I did:

  • The Plant grow bed is a normal tote from a big box store
  • The non-soil growing medium is a combination of gravel and Hydroton (clay balls)
  • The bottom is a standard 10 gallon aquarium with a board on top as a lid
  • I used the smallest submersible pond pump I could find and a 1/2 inch rubber hose running from the pump to the grow bed
  • An ingenious flushing system was pioneered by Affnan (you can Google Affnan mini bell siphon), allows the water to fill the grow bed, and then it flushes like a toilet back into the aquarium. If you don;t want to build one like I did, you can buy one here.
  • The water level in the aquarium cycles from 90% full to 50% full and back to 90%, over and over, providing oxygen to the fish.
  • The only electricity is what is used for the pump, which can be place on a timer to run every couple of hours or you can let it run continuously.  I also added a very small electric aquarium heater because our nights get cold in Ohio.

If you pop cuttings into a system like this they will root faster than I have ever seen.  Seeds sprout faster than I have ever seen as well.  The plants love the flooding and draining, and will quickly build up massive root systems.  When ready to transplant they are easy to remove from the gravel.

Cycling up a new Aquaponics System

If you have ever set up a fish tank, you know that at first, things are not so kosher for the fish, and the water gets cloudy.  Eventually, enough bacteria builds up in the bio filter, and then one day: pop!  The whole thing gets crystal clear.  That’s the same with aquaponics, except the “bio filter” is now a grow bed filled with plants.
Initially, the fish waste creates a lot of Ammonia and other bad things that fish don’t like, and the plants and gravel don’t filter it out right away.  Basically if you build a Micro Aquaponics system just know that for the first 2-3 weeks things will be touch and go and both fish and plants could die.  But once the initial cycling up period is over, the thing will basically run itself.

I have included links to my Youtube Channel videos where I show a little more detail on some of this stuff.  Good luck and feel free to ask questions in the Comments section.


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