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On aquatic life

Informatics is a great science. When you want to do it yourself, all you need is a computer, which merely everyone has at home.

Physics is very supportive, when you have a little bit of money to spend. With lego-technic or countless other beginner-friendly building sets for electric or mechanic installations, you can even get into robotics.

You want to do biology? This could get a little more difficult. The green companions (e.g. plants) of some of my friends are impressive. However, when you want to go deeper or to be more specific smaller, you will stumble on unusual problems.

Some time ago, I got inspired from an article of a university project, where students were tasked to build and maintain the cheapest possible bioreactor and grow a population of a specific bacteria culture. As my education was heavily biotechnology related, I always feel the desire to get back to it.

Out of this inspiration and desire, I tasked myself to grow phytoplankton on a budget. These merely small and simple organisms allow us to live on our wonderful earth. They are responsible for around 50% of all oxygen generated on our earth. Fuck trees (just kidding, please don’t). Source

Man, these fuckers kept me busy for a long time. While aquarium or fish tank hobbyists have green algae as a personal enemy, they were astoundingly difficult to get on their own. They mostly work like regular plants. You don’t need to water them (obviously), but if you want them to grow, you need to supply them with fertilizer and trace elements. In a usual aquarium, this is mostly given and as you want more complex organisms to grow, algae are usually not a thing you want to see. They are an indicator for unhealthy or wrong concentrations of required fertilizers or trace elements. With this in mind, you will mostly see articles about how to avoid algae. This is probably the reason why it took me so long and puzzled me so many times.

To start the project, I ordered some chemicals to be able to mix my own fertilizer, as I read, that most aquatic plant fertilizers are mixed to avoid algae growth. Reaching back to the start of the article, when you go down the Chemistry route, you will definitely land on some lists. My ordered chemicals came from Bulgaria, had big Cyrillic letters on the package and were labeled as “cosmetic ingredients”. If the police ever searches my home, I probably would need to explain, that I am not intending to build bombs. This article is a safety measurement. On a site note, Chemistry is made for masochists. If you know, you know.

Now, my first big error was getting the concentration of chemicals hilariously wrong. I did not research about realistic concentrations, so my shot in the blue was probably around the hundredfold of a sensible concentration, which is pretty toxic for plant growth. My god, I am glad, I did not set up an aquarium for fishies. I spotted the mistake eventually, when I looked up sensible concentrations. Source

The second and probably longest phase of the project was the technical setup. I wanted to make my aquarium mostly remote-controllable or at least schedule-able with a Raspberry Pi. The concrete goal was to add fertilizer regularly in controlled amounts. I tried to build pumps out of 3D-printed parts and some spare parts lying around. I got my first steps of 3D-printing, which was very fun. However, in the end, I just bought pumps. Unfortunately, I had problems with those as well. They were specified to work with 3V to 3.7V. Without actually pumping medium, this specification is correct, but in practical use they sometimes had difficulties to start. After extensive troubleshooting to my circuit design, I just used 5V. I guess, I’m a newbie on many things here, but you have to start eventually.

“Okay, setup’s finally fine. Why do I still have no algae?!” – Yeah, turns out, you need to start somewhere. I finally ordered an already established colony of algae to start my batch. While you probably always have algae in an established aquarium, you won’t have, when you start with tab water. This might seem self-explanatory, but actually many organisms float around in the air you breathe. Ever wondered where mold comes from? I started this project with the expectation, that algae will also be literally everywhere. It might be, but now I think, that you need to be very patient to get a colony growing.

This is the culture (Scenedesmus sp.) I finally bought, when no other problem could be identified. I usually tried it with tab water or water from local lakes. Maybe this would work, If I had more know-how or time. Even a large colony takes time to produce biomass.

Now look at them producing tiny little bubbles of oxygen. I also think, the rocks help for the algae to be “comfortable”. I don’t exactly know why.

The complete assembly of devices and glasses usually sits in a flask-holder. However, it looks so eerily like a bomb (cables and lights and fluids and tubes), that I will not share a picture.

This was a side project, which took some pressure from Nahual. My work schedule currently forbids working wholeheartedly on Nahual (also because I’d like to have a private life). Feel free to comment or contact me if you know a lot or nothing at all about algae. Either way, discussing science is always fun.

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