Check the listing for details. API Nitrate NO3 test kit Fresh & Salt Water (90 Tests). Condition: New. Listed at 13.99 USD. Nitrate buildup in aquariums 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 or organic pollutants. Up to 90 tests with this API Kit. Two dropper bottles for accurate dispensing of test solutionsEasy-to-read instructions and color chartNon-staining glass test tube with snap-tight cap Aquarium Pharmaceuticals Fresh And Salt Water Nitrate Test Kit measures nitrate (NO3) in freshwater and saltwater aquariums. The enclosed instruction booklet will tell how to test for nitrate, what the results mean and how to improve water quality and fish health. Fast, easy and accurate. Reads 0 to 160 mg/L or parts per million (ppm) of nitrate. Child resistant safety caps. The Fresh And Salt Water Nitrate Test snap-tight cap.