During the running-in phase of a new aquarium, after treatment of diseases or filter change, a build-up of nitrite (nitrite peak) can occur, as the number of filter bacteria is not sufficient to convert the toxic nitrite into nitrate, which is a nutrient for plants. A nitrite content of 1.0 mg/l can already be harmful to fish. sera Nitrit-minus offers quick help in severe cases of contamination and immediately removes up to 1.5 mg/l nitrite per dose. It converts nitrite into organic amines which are used by the filter bacteria. Nitrit-minus is well tolerated by ornamental fish, invertebrates and plants and can be dosed up to 5 times higher than normal. eliminates 1.5 mg/l nitrite per dose in a short time prevents a nitrite peak and offers immediate help in severe cases of pollution binds nitrite and converts it into organic amines, which are used by filter bacteria Tip: You can determine the nitrite content in the aquarium water using the sera Nitrite Test (NO2) sera Quick Test. What is a nitrite peak, when does it occur and what can I do to solve the problem? We answer these and other questions in our publication Interesting facts about nitrite spikes.