This is for 1 Söchting Oxydator Mini. Also includes 2 little pieces of catalyst, 2 x 75 ml containers of Oxydator solution and of course instruction sheet Using a patented method, Söchting Oxydators produce normal and activated oxygen in the aquarium by means of Oxydator solution and special ceramic catalysts. The activated oxygen decomposes particularly putrid matters and toxicants and, thus essentially improves the well-being of fish and plants. Pure oxygen created by the Söchting Oxydator is mostly immediately dissolved in the water, so that there are hardly any bubbles produced. Due to the Oxydator's oxidizing capacity, the water quality will be improved and harmful contaminants in the water will be neutralised and In the summer, it is effective at fighting algae. The benefits of adding hydrogen peroxide to an aquarium in cases of acute oxygen deficiency, water putrefaction and water turbidity, have been known for a long time.