According to one forum Aquaponics is the integration of aqua-culture (fish farming) and hydroponics (growing plants in water). The natural bacteria in the ecosystem converts waste from the fish to nutrients which is absorbed by the plants and removed from the water. This growing method requires minimal water usage and no chemical fertilizers while providing organic produce and fish from the system. After many hours of research and experimentation my Aquaponics project is a success! I probably could have got the system up and running sooner but some of the parameters I put in place proved to be challenging. The idea was to keep the system small, run on solar power and design an electronic circuit to control and run it all.
I must give credit to a couple of real awesome websites that provided great ideas and inspiration for this project.
Main Aquaponics System
Backyard Aquaponics provided most of the design ideas to get me started. And their article on using blue barrels caught my attention as I had some old blue barrels that I wanted to re-use from our old floating dock. I wanted to design the system to use just one pump and from these examples I settled on designing my Aquaponics system as a CHIFT PIST system (Constant Height in Fish Tank, Pump in Sump Tank). The picture below outlines the general idea.
Here is a picture of my fish tank.
The pipe running along the top comes from the pump and the fittings along the pipe provide aeration or dissolved oxygen to the water.
Here is the venturi drain inside the fish tank.
The idea here is that the solids from the bottom of the fish tank will sucked up by venturi action once the water begins to flow out of the overflow at the top of the fish tank. This is where the CHIFT comes from as the water level in the fish tank remains constant (it actually fluctuates a little but normally only the height of the drain pipe which is 2 inches). The ‘T’ at the top prevents the system from draining the fish tank. The fish tank is a blue barrel lying on it’s side with a square access hole on the top.
From here the water drains into my two grow beds which are another blue barrel cut lengthwise and lying on their side. I used some of the 2 X 8’s from the floating dock to create a cradle for the grow beds as they would get quite heavy with water from time to time (actually about every 30 minutes during daylight hours – more on this later). The water fills the grow beds to a specific height which is determined by my bell siphons. Here is the theoretical picture.
And here is what mine looks like in the grow bed before I put the grow medium in.
Once the water level in the tank reaches the height of the inside pipe it creates a siphon and drains the grow bed to the level of the holes along the bottom. The water is drained into the sump tank which is made of a third blue barrel cut in half horizontally. These two halves sit below my grow beds and are piped together to provide the capacity of a full barrel. Each of my grow beds drains into one half of the sump tank but because they are piped together I am able to use one pump.
The last piece of the design is the aeration which I decided to use three. One that you saw above on the pipe that fills the fish tank and I put one on each of the drains from the grow beds. This aeration provides the fish with oxygen as well as the plants. The higher the dissolved oxygen levels in the water the better. Here is a picture of my aeration snorkel.
The theory behind my aeration snorkel is that it creates a vacuum that sucks the air into the water. Here is a view inside the pipe.
This results in air bubbles entering the water which provides the dissolved oxygen needed.
The inspiration for my controller came from Backyard Aquaponics and TheBackShed.com website article on using a Picaxe micro controller to run a pump. I spent many more hours researching the Picaxe micro controller at their website www.picaxe.com The Picaxe controller is a programmable chip that is a low cost solution designed to be the brain of an electronic project such as this. I purchased most of the electronic components I needed from Solarbotics out of Calgary Alberta. Their focus seems more around robots but they had all the components I was looking for. Doing some estimation for pump sizing I decided to go with a 12V submersible pump that provided 14 Litres per minute (220 gallons per hour) and decreases depending on the amount of static head (how long the vertical pipes are). My hope was that I would be able to cycle the system once every 30 minutes. My calculations suggested the pump should be able to fill the grow beds in about 6.5 minutes. The final system needed 5 minutes and 10 seconds to fill both grow beds! The pump was sourced from LightObject out of Sacramento California.
The general idea is to run the water pump long enough to fill the grow beds until the bell siphon tripped, wait a while and start over again. This cycle is designed to run during daylight hours. The solar portion of this project got shelved as my batteries would not hold a charge so I am using a recycled computer power supply for the DC voltage required! Perhaps I’ll add the solar powering to the system sometime in the future.
The steps above are summarized to a great degree as I had many challenges along the way. I am very pleased with the results!
The plants above have been in the system for one week now and look very healthy and happy!