Nutrafin Nitrite Fresh & Marine Aquarium Test Kit comes equipped with full complement of test equipment: test pipette glass test tube and cap lab base instruction booklet. Regular testing is essential for new aquarium installations when medicating adding more fish and after having performed filter maintenance. Persistent nitrite levels can indicate over crowded aquarium conditions over-feeding or inadequate filtration. The Nutrafin Nitrite Fresh & Marine Aquarium Test Kit helps maintain proper nitrate levels for your tank(0.0-3.3 mg/l). Nutrafin Nitrite Fresh & Marine Aquarium Test Kit Features and Benefits:. - Best used with Biological Aquarium Supplement Nutrafin Cycle to determine nitrate level (0.0-3.3 mg/l). - Easy to follow directions. - Essential in monitoring your tanks water quality.