Tropic Marin Tropic Marin Nitrite/Nitrate Test (Freshwater/Saltwater)

For determining the nitrite and nitrate concentration

Nitrite (NO2–) and nitrate ions (NO3–) are formed from ammonium (NH4+) as part of the nitrification process. Nitrite, which is highly poisonous to freshwater species, is produced in the first stage of the bacterial process. If the nitrification process works, nitrite is converted to nitrate in the second stage. Higher concentrations of nitrate in saltwater aquariums will end up inhibiting the growth of delicate corals. A danger posed by high nitrate content for all aquariums is the strong boost it provides to algae growth. In rare cases, nitrate shortages can also occur. Therefore, the concentrations of nitrite and nitrate in the aquarium water should be tested regularly.

As a general rule, the nitrite concentration should be less than 0.2 mg/l (ppm) in all aquariums wherever possible. The nitrate concentration should not exceed 20 mg/l (ppm) in saltwater aquariums. When nurturing hard corals, the aim is to keep the nitrate concentration below 10 mg/l (ppm). It is advisable to keep the nitrate concentration in freshwater aquariums below 50 mg/l (ppm). Lower limits for nitrate depend on the general conditions in the aquarium.

With the Tropic Marin® Nitrite/Nitrate-Test the nitrite and nitrate concentrations can be determined using a finely-tuned colour chart which has a range of concentrations for nitrite of between 0 – 2 ppm and for nitrate of between 0 – 50 ppm.


  • Measurement range: NO2 0 – 2,0 mg/l (ppm)
  • Measurement range: NO3 0,5 – 50 mg/l (ppm)
  • Accuracy: NO2 0.02 mg/l
  • Accuracy: NO3 0.5 mg/l
  • For determining the nitrite/nitrate concentration in aquaria
  • Sufficient for approximately 50 applications