Measures nitrate levels in both fresh & saltwater aquariums. Tests nitrate levels from 0 to 160 ppm. 90 tests per kit Nitrate build-up in aquarium is often an indicator of declining water quality. High levels of nitrate are frequently associated with poor fish, health, algae growth, and a build-up of organic pollutants. Nitrate is produced in the aquarium by the biological filter. Beneficial bacteria in the biological filter converts toxic ammonia and nitrite into nitrate. A high level indicates a build-up of fish waste and organic compounds, resulting in poor water quality and contributing to the likelihood of fish disease. Excessive nitrate also provides a nitrogen source that can stimulate algae blooms. The Nitrate Test Kit is a fast, easy and accurate test for freshwater and saltwater aquariums. The kit contains two dropper bottles for accurate dispensing of test solutions, easy-to-read instructions and color chart, a non-staining glass test tube with a snap-tight cap, and instructions.