The "Vodka Method": Algae control by adding alcohol to your aquarium

In the first place the 'Vodka Method' is used to control the growth of algae in your aquarium. But the way it works is very fascinating and has some interesting 'side-effects'. To apply this method successfully requires understanding of biological processes in an aquatic biotope.

The idea is that bacteria are competitors of algae, since they consume the same nutrients. But besides nitrates and phosphates bacteria need something else to multiply: carbohydrates. These can be provided in high concentration through alcohol, thus high concentrated alcohol i.e. ethanol. Ethanol is a natural product and quite cheap available in pharmacies.

A dosage that works fine for me is: 100 ml of ethanol with 400 ml of water. From this mixture I add daily in the morning (important!) 10 - 20 ml per 100 l aquarium. This dosage must be achieved gradually, starting from 1 - 2 ml, because the bacteria consuming this alcohol must multiply in a controlled way. This means they establish themselves on surfaces, such as stones, sand, plants, glass, filter material. On this surfaces other forms of life can feed on them or water currents carry them to anemones and coral who highly appreciate this extra food. Even more, filter feeders like sponges, sea squirts, gorgonians, tube worms... feed mainly on infusorians. I had a good multiplication of zooplankton.

                                   

Overdosing would cause bacterial bloom, i.e. bacteria don't multiply on surfaces, but in the water itself. The water gets cloudy. This condition must be avoided, because -  other from algae - bacteria produce co2. A bacterial bloom can consume oxygen to a life threatening degree and is difficult to get under control.

This is also the reason why ethanol must be added in the morning, because in the night co2 levels rise anyway, you would not double this effect by fueling bacterial metabolism through ethanol dosage. During the day co2 can be consumed by plants and could provide even an additional fertilizer - especially in planted aquariums, both salt and fresh water.

All of this may sound very complicated and dangerous, but actually it is quite safe, when applied carefully and with understanding for the biological processes. I am very satisfied with the results, because it was the only way to safe a stone coral from being totally overgrown by algae.

I hope you will achieve good results with this cheap yet natural way of algae control...