The Dennerle Dosator made from high-quality plastic works according to the principle of osmosis. Water from the aquarium "seeps" through the semi-permeable special membrane into the reservoir, pushing the nutrient solution drop-by-drop via the riser into the aquarium. This has two effects: firstly the aquarium gets the amount of fertiliser it needs, and secondly: the Dosator becomes a "tank indicator": as the water enters bit by bit and pushes the fertiliser into the aquarium, the fertiliser-water mixture in the Dosator becomes increasingly clear. When the contents of the dispenser lose their colour (S7 orange, V30 yellowy-green) you know it is time to fertilise.
Aquarium plants benefit from the constant, even supply of nutrients like in nature. This ensures healthy, even plant growth and allows the aquarium to shine with magnificent, rich green splendour. The disadvantages of an excessively high nutrient concentration caused by bursts of fertiliser are a thing of the past. And the best thing: The overall lower nutrient level and the need-based supply of nutrients to the plants is extremely effective in preventing algae growth.