Colombo no2 nitrite Pond water Test Kit, Nitrite (NO2) is produced from the breakdown of ammonia in the filter.
Nitrite is highly toxic to fish, but is usually removed from the water by the bacteria which live inside the filter.
However, in new ponds and aquariums, or if the filter bacteria are damaged, the nitrite level may become toxic.
The only way to know what the nitrite level is, is by testing the water with a Nitrite pond test kit.
Colombo Nitrite Pond Test Kit contains 40 tests.
How To Use Colombo NO2 Nitrite Test Kit: