Introduction: Classroom Aquaponics #1
I've always liked keeping a fish tank and surrounding myself with plants. Starting an aquaponic bottle garden seemed a logical next step. The plants filter the water and the fish give the plants nutrients. I built this system in my classroom as an on going science experiment and to see if something like this would work. I wanted to use recycled materials when possible so I chose these 2 L bottles as the grow area for this Hanging Aquaponic Bottle Garden. I won't give you a lengthy explanation of the nitrification process because so many have done it before me. I only wish to show how and what I did.
Step 1: Building the Bottle Tower
When I started this project I didn't have many tools but I did have a Soldering Iron which I found was invaluable. The other materials are readily available anywhere.
1.) Use five 2 L plastic bottles to make one tower.
2.) Cover half of the bottle with paper and tape off all areas you don't want painted.
3.) Paint the bottles to block sunlight out in order to stop algae from growing inside the grow medium.
4.) Melt holes into the bottom of the bottle with the Soldering Iron in a circular shape in order to create an opening for the neck of another bottle to be connected.
5.) Trace out shapes to be cut out of the bottle with a black marker. I cut out a rectangular shape on one side and a circle shape on the other.
6.) Use the Soldering Iron to melt a hole big enough for you to get scissors in and cut out your shapes.
7.) Choose the best size of hole for the water to run through. Now you can reach in and screw on the cap and secure one bottle to the next. Note: (After a few months running I found that the cascading water running down over the plant in some cases caused the plants to rot because of being too wet. I improved this by simply running a rubber tube down from the cap of one bottle to the roots of the next plant.)
8.) Use 10 meters of 5mm width cloth rope to wrap around the bottles and hang it from the concrete screw hook in the roof. Unroll the rope it and lay it out on the floor to find the approximate center. Start wrapping the rope around the middle of the bottle and up around the neck of the next bottle and continue.
9.) Once the rope is wrapped around all sections hang it from the concrete screws that you pre-inserted in the ceiling. I asked for a professional on campus to drill in these three hooks.
10.) Connect the rubber tube to the pump and run it up into top two bottle that were cut in half. Use a tube splitter to divide the water flow equally into the two towers. Note: (I always wanted three towers but the tube splitter I bought didn't split the flow of water up equally into three so I had to settle for only two.)
Step 2: Split the Water Flow Into Three.
I ran this system for a few months before I got around to finding a solution to our water splitting problem. I came up with this simple filter that splits the water flow evenly into three streams.
- two 2.0 L bottles
- water filter floss
- a three way water tube splitter
- two pieces of rubber tubing
- duct tape
- soldering iron
1.) Use scissors to cut the two plastic bottles in half, lay two layers of water filter floss on the bottom of the two bottles.
2.) Cut out a long narrow slot in the top of the filter to allow room to get the tube splitter in through the top.
3.) Use the soldering iron to melt a hole large enough to stick one head of the water tube splitter through.
4.) Apply duct tape to the middle of the two bottles so no water leaks out.
5.) Melt three small holes in the bottom of the filter to allow water to flow out evenly into three streams.
Step 3: Everything Else.
Just like any fish tank there must be some sort of balance or fish start dying. Here is a must have list of things needed to complete this project.
- Fish tank. It must be big enough to accommodate at least 10 fish.
- Water. Water must be added daily because of evaporation (its best to let the fish dirty up the water before inserting plants into the system so that the nitrification process can take hold)- Fish. (I started out with 30 small feeder gold fish)
- Heavy duty water pump. It must be powerful enough to push the water upwards to at least a meter high.
- Rubber water hose. One meter long rubber water hose to bring the water from the pump up into the filter at the top.
- Gravel. Needed to let solid materials settle in the rocks at the bottom of the tank.
- Water plants. Fish like plants to hide behind and the plants give oxygen to the water.
- Conventional water filter. Needed to act as a back up system and to add oxygen.
- Fish food. Fish food is something that is critical to the survival of your system.
- Expanded clay balls. I chose expanded clay balls as the grow medium because they are very light and porous. Micro organisms are said to grow in and between pores of the clay balls. These micro organisms are vital to the nitrification process.
- Plants. I first used strawberry plants and they did pretty well but the leaves started to turn yellow indicating a lack of minerals. I had hot pepper plants for a while. Currently there is a tomato plant and Peace Lilies growing.
- Water heater. I found running warm water over the roots gave a better result.
- Algae Eater. Every fish tank needs a algae eater in the tank and I chose a Plecostomus catfish.
- An electronic timer. Needed to turn your pump on and off. I use a wifi timer that can be configured to turn on and off at any time I program it to. It even has an accompanying application for my Iphone. The App is in Chinese and my Chinese is poor so programming it was challenging. The wifi plug randomly turns the pump on and off whenever the wifi connection is poor. It works great and there is no need to program it specifically.
Step 4: Trouble Shooting Over Time.
I purposely did not publish this instructable before it had some age to it. I knew that problems would arise over time. Towards the end of the second semester before summer break my system was 6 months old and had I addressed all the problems that I encountered up to that point. I learned a lot from other examples of other aquaponic systems on the net but never read anything about potential problems. Here is a list all the problems I found and how I fixed them.
1.) Out of control algae growth. Even though I had a hard working algae eater the algae was growing to rapidly. This was due to direct sunlight coming in through the window into the tank. I put a large piece of dark construction paper in the back of the tank to limit the amount of sunlight able to enter the fish tank. This cut the algae grown tremendously.
2.) Cascading water flow. Originally I designed the water to cascade down. I found this tended to rot some of the plants. I fixed this problem by inserting a rubber tube from the end of the cap of the bottle down into to expanded clay balls below. This solved my rotting plant problem.
3.) Clay balls sometimes block the flow of water. A few times a clay ball or two got lodged to close to the open end of the rubber tube that brings water down into the next grow area. I cut a small piece of water filter floss and placed in the neck of each bottle so to prevent any clay ball from blocking it in the future.
Step 5: Finding the Right Plants.
I had strawberry plants to start with and they did well but never thrived in this environment. I planted one tomato plant and it grew out of control. It soon dominated the entire window. It produced few tomatoes but the ones that did grow were very delicious. The Peace Lily does well in a watery environment so I inserted 8 plants into the system.