API Nitrite Test Kit
The API® NITRITE TEST KIT reads nitrite levels quickly and accurately in your tank, and tests parameters from 0 to 5 ppm.
Nitrite is produced in the aquarium in the forms of fish waste, uneaten food, and by nitrifying bacteria in your aquarium’s natural cycle as it breaks down ammonia. Low levels of nitrite inhibit respiration and suppress the immune system, while high levels cause suffocation in fish.
More details on this product, including full instructions, can be found HERE.
Also available in the Master Test Kit HERE.