API Nitrite Test Kit API Nitrite Test Kit is a freshwater and saltwater liquid test kit that measures nitrite from 0 to 5 ppm, helping aquarists monitor cycling, biological filtration, and invisible water problems that can harm fish. API Nitrite Test Kit for Freshwater and Saltwater Aquarium Cycling Nitrite is produced as part of the aquarium nitrogen cycle and can rise when fish waste, uneaten food, or biological-filter imbalance affects water quality. Low nitrite levels can stress fish, while higher levels can interfere with respiration and become dangerous quickly. Liquid Nitrite Testing from 0 to 5 ppm for Fish Safety Measures nitrite from 0 to 5 ppm. Suitable for freshwater and saltwater aquariums. Useful during new aquarium cycling and after biological-filter changes. Helps detect nitrite problems before they are visible by appearance alone. Supports weekly monitoring in established aquariums. Includes colour card for comparing test results. Helps guide corrective action when nitrite is present. API Nitrite Test Kit Monitoring Notes Product type: liquid nitrite test kit Test range: 0-5 ppm Use for: freshwater and saltwater aquariums New aquariums: test every other day during initial setup Established biological filter: test weekly Initial biological-filter establishment typically takes about 4-6 weeks. API Nitrite Test Kit Directions Rinse the test tube before use. Fill the capped test tube with aquarium water according to the instruction manual. Add the nitrite test solution as directed while holding the bottle vertically. Cap and mix the sample according to the instructions. Compare the colour result to the included nitrite colour card. Test every other day when a new aquarium or pond is first set up. After the biological filter is established, test weekly for routine monitoring. Rinse the test tube after use and do not pour test contents back into the aquarium. What's Included One nitrite test solution bottle One capped test tube One instruction manual One colour card