Salifert Nitrite (NO2) Test Kit (Reef)Nitrite is a substance that is toxic to fish and invertebrates. It is a misconception that once a tank is through its cycle (first 3 or 4 weeks) that nitrite has vanished. Many nitrite test kits suffer from interference by amines (such as naturally occurring and essential amino acids) resulting in a too low measured value especially if the nitrite concentration is relatively low. Nitrite is converted to nitrate in properly cycled aquariums. The thus