Some days ago, arriving at my desk I found a bunch of pieces of wood neatly cut and stack into an old wooden veggie box. It captured my attention for few moments but I couldn’t actually tell what those pieces were and if they were scraps. This until Ande came and told me it was for an aquaponic system. From Barcelona.
Did they really ship that stuff all the way from Barcelona to London? I thought.
No, of course not.
You could take care of it, Ande said just before I left to Italy for a conference.
And so it started my adventure with aquaponics.
Once back I took the vintage veggie box with all the pieces inside and I started assembling it.
The design is easy and conceived to be assembled without tools, screws or nails. It could literally be built by kids with little supervision. Education is actually one of the main tasks for the kit, but not only for children. The aquaponics system combining hydroponics (growing vegetables in absence of soil) and aquaculture (fish farming) would play a crucial role in how we will source food in the next future. With this, almost anyone can stay ahead of the game and transform the goldfish bowl into something more entertaining and even productive.
The manual showing how to assemble the kit step by step and a time-lapse on Youtube is all you need to build it. The structure is divided into two main parts: the body and the blood. The first is the wooden structure, the second id the water and the system that makes it circulate from the fish tank to the growing bed where the plants grow. There are then the nervous system and life.
Although since at the moment they only released the instructions for the body. So we built it and we started playing around a bit with the blood (which sounds gross but it’s actually fun and cruelty-free).
To make it easier to follow and integrate this description with the official manual it will keep the same division of the structure in the four parts.
If you don’t try to make a time lapse and do it, again and again, to find the perfect frame and sequence to assemble the wooden part will take about 15 minutes, maybe less.
Here’s how it looks like once assembled.
And here’s the time lapse we made.
When it is built make sure to find the right spot for it as you might not want to move it once the tank is in, the water is into the tank and the growing bed is full.
Talking about the costs I will break down them to any stage of the assembling to the final, operational system. So to this point, we have the timber and the CNC milling. As specified by the open source manual provided by the Aquapioneers team all the pieces fit in a standard 1200x2400mm or 4×8 feet board.
We opted for a 25mm thick multilayered board in our storage. Recycled. The CNC work instead was offered by our friends from the lab_083. On the other hand, to be fair and assuming you’re not so lucky the cost of the timber would be around 50£. The CNC work cost, thanks to the very complete files that come with the kit’s open source folder also featuring tips to program the machine, may be reduced to a quite good 100£. Yet the price may vary according to who you ask to do the work but some fab lab might also do it for free. So do some research first and ask around, they might also have some recycle timber to sell for cheap. Just be sure it is resistant enough and follow the instructions in the manual.
Green Lab system
The body is therefore done and it’s time to set up the system where the blood runs.
The first thing to do then is to seal the growing bed, the box at the top of the structure, as it will soon be flooded. To do that we used a fine pond liner easy to find in garden shops or aquarium shops. Here the price could change according to the quality or the shop. You don’t necessarily need it to be expensive, just be sure it won’t start leaking in your living-room.
Green Lab system
EPDM rubber pond liner
To make the liner fit the box is not so straightforward but it doesn’t need to be extremely precise. It would rather be better a little more abundant than too short. My suggestion is to put the liner at the bottom of the box, then starting from one of the long sides fasten it to the outside using a staple gun (or pins). Do the same to the opposite side and then to the short ones folding the corners and fastening them to the outside (avoid damaging the liner from the inside or it would leak). Eventually cut the excess. If you place the liner wisely you save some, still useful, pieces so start from a corner of the sheet and try a couple of options before fastening and cutting. When the box is finally sealed then you need to cut a cross into the liner. On the bottom of the box, there are two holes to allow the water to flood into the box and drain into the fish tank below. Through those holes run the pipes. We actually decided to use only one of those, cutting it bigger to fit a recycled spigot/socket tank connector.
For those building it in the UK, all our pipes are U-PVC (unplasticised-PVC, food safe) generally sourced at Plastic Pipe Shop
Green Lab system
spigot/socket tank connector
With a sharpen lancet cut a cross slightly smaller of the diameter in correspondence of one of the holes (or one of them if you decide to share our choice we will explain when talking about the pump) and fasten the tank connector into it.
Once the connector is placed, cut a piece of pipe of the diameter that fit your tank connector 12cm long. The length is determined by the depth of the growing medium considering it a couple of centimetre above the edge of the box. The pipe we’re now discussing is the draining one so it is also meant to set the higher level of the water into the growing bed which should allow a 2/3 centimetre of it to stay dry. This will prevent the trunk of the plants from rotting.
In order to make the flooding and draining system more effective it needs to be quite slow and at the end of the second phase, before the cycle starts again the water has to be drain as much as possible. This way the roots aren’t constantly soaked and don’t rot. To optimise the water system some holes needs to be drilled into the pipe to slow down the flooding and allow the water to drain completely when the pump stops.
This requires a few tests and it is quite empiric as it really depends on the power of the pump, the diameter of the pipe and the one of the drilled holes. Moreover, if you drill too many holes, as we did at the beginning, the water won’t reach the desired level and the plants won’t get the nutrients.
We did our tests, making more holes than needed and then closing them with stainless screws till we got the optimal result. Which means that the draining rate is just lower below the flow rate of the pump. The following instructions are for a system using a d 32cm draining pipe and an 8w 500l/h pump.
Our tests show that in this setting 11, 3mm diameter wholes make the perfect balance between input and output. We drilled them at four different heights, but actually, it’s the number that really matters rather than their position. Except for the ones at the bottom that need to be as low as possible.
The other end of the connector will host another pipe of the same diameter going right into the fish tank below. So it’s time to put the tank into the structure. The body is meant to perfectly match with a 60x30x30cm tank which means 54lt capacity. I would suggest to fill it for the 4/5 of the capacity. Let’s say 40lt of tap water. This will be your reservoir. There’s actually no need to use distilled water as it will run for a few days before hosting any life so the chlorine will evaporate and other minerals will be filtered by the growing bed.
The best way to fill the fish tank once it is in place is actually from the upper box, so fill it and the water will drain down into the tank. This way you will also test if the box leaks or you sealed it well. A wise tip would be to put a dampening layer under the tank in order to prevent cracks in case the wood moves or it is not perfectly levelled. This could be Styrofoam of any other thick foam.
Once the tank is placed insert the pipe you’ve previously cut into the lower end of the tank connector at the bottom of the growing box. I suggest to cut it to 2/3 of the fish tank in order to keep it always under the water level and prevent loud splashes ( 30 cm.)
At this point the circulatory system is almost ready: the blood and its vessels are in place but it wouldn’t move without a heart pumping it into around the system. Our heart is a standard aquarium pump suitable for tanks up to 125lt. Considering the capacity of the tank you could also opt for something smaller but it would mean to test again with the draining pipe. To pump the water from the fish tank up into the growing bed we went for the easiest way. We attached a d18/12mm flexible pipe to the pump and stick it into the box. That looks lazy but it’s also the most versatile way, less time demanding and more effective for small pumps.
Green Lab system
12mm ID x 18mm OD
THE NERVOUS SYSTEM
The nervous system is basically all the electronics that support life in the kit. In spite of being so crucial, it is pretty simple. You just need a multiple socket to plug the pump and the light into. The light in our case is a recycled 48w 2 lines neon we needed to adapt to the structure as it has been designed to host a specific LED lamp. The hack was extremely low tech tough. We just stuck a piece of timber with two hooks across the existing structure and hanged the lamp. To keep it as close as possible to the growing bed and let the sprouting seeds the get the most of the light we attached the lamp to a couple of pulleys. Chains or strings could also be a good alternative.
In order to make the system more hands-off as possible, we used two timers, one for the lamp and one for the pump. You can have a couple of analogue ones for very cheap and you can forget to switch the light on and off. Although it’s even a better deal when it comes to the pump as it is supposed to be switched any few minutes. This system, for instance, takes around 10 minutes to flood and drain completely so the pump is switched on and off every 15 minutes (the minimum possible setting in an analogue timer).
The nervous system is meant to go on the small shelf below the fish tank but we would suggest to collocate it away from any possible water leakage to prevent unwanted interactions with water.
Green Lab system
around 9£ (set of 2)
around 9£ (set of 2)
It’s now come the time for the most thrilling part. The reason why we have built all this: life. We’ve already said that aquaponic combined hydroponic gardening and fish culture so there are two different typologies of life in the system. On the top, into the growing bed, there are the plants while into the tank at the bottom there are the fish.
There are a wide variety of plants you can grow both edible or just decorative. We chose to grow a rare variety of beans (golden stripes beans) from Italy and chilis.
To be able to grow plants you first need a substrate which is generally expanded clay pebbles. The box contains around 17kg of pebbles. A good tip would be to wash them before introducing them to the system in order to get rid of most of the dust that would dirty the water. We also suggest putting a wider pipe around the draining one, taller than the level of the substrate to prevent the floating pebbles to go through the draining pipe into the fish tank. Before putting the expanded clay into the box cut a 22cm section of a D11cm pipe, drill a few holes into it and put it around the draining pipe inside the box.
Green Lab system
expanded clay pebbles
Now the growing bed is ready to host the vegetable life, but to the system to be complete fish are necessary. Fish provide the nutrients for the plants.
Fish are the most delicate element of the system and before introducing them to the tank you need to be sure the environment is suitable for them to live and stable. The first thing to do is letting the water run for a few days. Be sure the water is clean before running the pump, let it sediment for 24 hours.
By the time the water values reaches the suitable range for the fish life, you could still grow plants successfully as we did, but you would then need to add some nutrients to the water. We added 20ml of organic seaweed extract into the tank. If you’d rather prefer waiting for the fish the main values you need to check and monitor are pH and Ammonia, Nitrite and Nitrate concentration.
To measure the pH we use a digital device you can buy in any aquarium shop from 15£ on.
Another option is a set of reagent that shows the values through colours in chemical reactions.
The optimal pH we’re looking for is between 6.8/6.5, so slightly acidic. Tap water is generally hard which means it is alkaline. An easy and effective way to lower the pH is by adding vinegar. If your water is too alkaline pour half a glass of vinegar, wait for a couple of hours and then test it again.
The other three are measured with the regents kit and show if the biofilter transforming fish waste into nutrients for the plants is active. To activate it the only way is to add some Ammonia to the water. It could be household ammonia or just half a cup of urine ( 100ml). The presence of Ammonia activates bacteria that feed themselves with it producing Nitrite. The Nitrites again activate other bacteria producing Nitrate that eventually is the food for your plants.
Green Lab system
pH metre (pen)
Therefore in a healthy, perfectly balanced system, you will have 0ppm ammonia; 0ppm nitrite and a good, rising amount of nitrate. But before getting to this point you will first have a high concentration of Ammonia without any Nitrite and Nitrate. Then, once the bacteria activate the Ammonia will lower down and you will start detecting some Nitrite but yet no Nitrate. Eventually, you will start seeing Nitrate when the biofilter is completely activated.
You would need the system daily and once all the values are stable for a few days you can finally add fish to the tank an keep controlling the values once a week.
About fish there are actually a few options you can choose from, considering of course that sea fish are not good neighbours for the plants upstairs. A good option is instead goldfish, strong and long-lived; or guppies which have a shorter life cycle but they reproduce at an insane rate and you can pack dozens of them into a rather small tank.
We’re still evaluating different options regarding fish but the pH of our water isn’t suitable for life. When we started measuring the pH it was 8.4 which is too alkaline for fish. To lower it gradually introduce kombucha vinegar sourced from Green Lab resident Kompassion.
Eventually, we needed to add Ammonia into the fish tank in order to activate the bacteria. Which means I had to pee into it. (Yes, I did it). It isn’t such a big deal, just make sure your mom hadn’t invited her friends for a tea. They might misinterpret your behaviour, you pervert!
The concentration of Ammonia in the urine may vary but with 100ml in 45lt of water, we had 80ppm which is a good amount to kick start the biofilter. A higher concentration in the water would sterilise it inhibiting the proliferation of bacteria. To facilitate and speed up the process a good tip is to add some water or a handful of pebbles from an operating system. Take a fabric bag or a cup with holes in it and let it soak in the water as long as needed.
It is actually quite surprising how fast it can be. Within a few hours since we introduced the Ammonia we could already see the whole filter was active.
The two pictures on the left show the measurements done with the reagent set.
In the first one from left to right, there is pH (blue), Ammonia (green) and Nitrite (purple). Comparing the colours with the chart we have the concentration of the values in a certain range.
In the second picture, we tested again the pH with the reagent for high range pH as the blue was over the chart’s range. The third tube (orange) shows the content of Nitrate that is the compound you eventually want to have in the system. The higher the concentration (ppm= part per million) the most nutrients are available for plants.
Ideally, we should soon see a growing quantity of Nitrate and a concentration of Ammonia and Nitrite tending to 0ppm.
at this link you have a real-time access to how our system is working from a chemical point of view. The Google sheet features pH, temperature and the concentration of the three critical compounds plus the notes on what we do to reach the desired result. No one of us has a background in chemistry and our whole attitude towards the topic is quite empiric and based on experience.
Notice: in light of the fact that we spilled 30lt of water on the floor turning our event space into a pool right the night before an event, we warmly suggest to secure the line to the structure in whatever way so it doesn’t fell out.