The activity of the bio-filter in the aquarium system can be divided in mineralization and nitrification.
The product of the mineralization process are ammonia and organic acids. The next step of decomposition is the oxidation (nitrification) of ammonia and ammonium to Nitrite (NO2).
Nitrite has a toxic effect on fish because it oxidizes hemoglobin to methemoglobin.
While hemoglobin is responsible for the transport of oxygen, methemoglobin lacks this ability !

Nitrite concentrations higher than 0,05mg/Lt (ppm) of NO2 are not acceptable keeping aquarium fishes.

For these reasons, the periodical analytical valuation of nitrite in the aquarium water should be considered, specially during the aquarium set-up and, periodically, to avoid the activity loss of the bio-filter system.

ELOS AquaTest NO2, as well as all the other colorimetric test kitof this line, grants an high precision thanks to several procedureslike the use of "RealColor" technology, an accurate system to calibrate the colours chart compared to the reagents; the validation of its quality, thrugh NIST (National Institute of Standard and Technology) certified samples, in order to grant accuracy and constant results; the carefull stock management to supply to our customers ONLY the most actual and fresh production batch.

HIGHLIGHTS:
Easy reading: "RealColor" technology.
High precision: thanks to the use of calibrated dropper
NIST validation: each batch is validated using NIST (National Institute of Standard and Technology) samples
High number of test per kit: up to 50 tests
""Safe reagents"": reagents and testing procedures are based on Low Risk Reagents. None of Elos test kit are based on Toxic Reagents.