Have you been wondering how our aquaponics system has been working? We will tell you all about what has been happening! We have learned a lot of things.
As you can see from the pictures, our lettuce is growing fast and looks very healthy. It is lush greenery. Our tallest lettuce plant measures 8cm.
In the third picture from the right you can see our 2 Gasana strawberry plants. They are measuring about 5 cm tall.
In our small 5 gallon tank we have 4 Zebra Danios and 1 male Betta fish. The Zebra Danios are fast and furious. Our Betta just likes to relax and hang out! They are seriously hard at work eating and producing emulsion. The good bacteria is working to turn the waste into food for the plants.
In our large, 20 gallon tank we have 1 Black Molly, 1 Dalmation Molly, 1 Balloon Molly, 2 red Mickey Mouse Platies, 3 Zebra Danios,1 Pearl Gourami and 4 Rasbora fish. When raising fish, the general rule of thumb is to have 1 gallon of water per every 3 cm of fish. Most of the fish in the tank are less than 3 cm. The Pearl Gourami is the largest at about 6cm long. We still have room for a few more!
To start off our large system, we transplanted some lettuce from the small system in one bin. In the other bin we planted 2 Gasana Strawberry plants. The lettuce does not seem to be growing very fast. The strawberry plants seem to be growing very quickly. We will make predictions about the plants and continue to observe what happens over the last months of school.
Aquaponics can be tricky to master. There are many factors to consider. Keeping PH and ammonia at a level that is good for both plants and fish is tricky.
Fancy Science Stuff
What is pH?
pH is a unit of measurement for hydrogen ions.
What is hydrogen?
It is a colorless, odorless, highly flammable gas
What is an ion?
It is an atom or molecule with a net electric charge due to the loss or gain of one or more electrons.
Those definitions are a little tough to understand for the average elementary school student. So let's explain it in an easier way!!
The pH scale tells us how acidic something is. Substances with more hydrogen ions are more acidic.
When I think of acidic substances, the first thing I imagine is vinegar. Acidic substances have lower pH values on the scale. Vinegar is about 2.4.
The opposite of acidic substances are called alkaline substances. These have less acid (less hydrogen ions) and a higher Ph Value. For example, soapy water has a pH value of around 12.
Fish need a neutral pH value. Water is neutral, at about 7. Fish would not like to live in vinegar because it is way too acidic! Fish also don't like soapy water because it is way too alkaline!
Most plants do better with a little more acid in their growing environment. They thrive when the pH level is between 5 and 6.
Since fish like neutral pH and plants like slightly acidic pH, this makes finding just the right balance for both fish and plants very tricky.
We would like our classroom fish tank water to be at around 6.5 - 6.8.. This should be good enough for the fish and the plants. Right now our system is a little too alkaline for the plants with a pH of about 7.
What is ammonia?
a colorless gas with a characteristic pungent smell. It dissolves in water to give a strongly alkaline solution. Fish waste can create ammonia in the tank.
When a fish tank has too much ammonia, it can make the water too alkaline for the fish. The pH of pure ammonia is around 12. This is very harmful too fish.
In fact we had some fish die in the beginning. The water was too alkaline for them. The ammonia levels were too high and our pH was close to 8!
We will keep you updated with how our pH and ammonia levels are doing!!