Colombo Nitrate Aquarium Test Kit (NO3), is produced from the breakdown of nitrite in the filter. 

Nitrate is relatively harmless to freshwater fish, but its presence can indicate a deterioration in the aquarium environment, and high nitrate will encourage algal growth. 

The only way to know what the nitrate level is, is by testing it with a Nitrate test kit.

Colombo Nitrate Aquarium Test Kit contains 40 tests.