Check the listing for details. AquaLabs Nitrite Aquarium Test Kit Freshwater Saltwater Testing Kit. Condition: New. Listed at 30.03 USD. The AquaLabs Nitrite Test Kit provides accurate, easy-to-read measurements of nitrite (NO₂⁻), a highly toxic intermediate in the nitrogen cycle. Even small amounts of nitrite can stress or harm aquatic life, making reliable testing essential for both new and established aquariums. Using a high-precision liquid reagent, this kit delivers clear colour results across a practical testing range suitable for routine monitoring and system troubleshooting. Test Range: 0 – 5 ppm Nitrite (NO₂⁻) Each kit includes enough reagent for 100 individual tests , offering dependable long-term monitoring of your aquarium’s water quality. Kit Includes: • High-accuracy liquid nitrite reagents • 5 mL glass test tube with cap • Dual colour charts for freshwater and saltwater in.