When there are insufficient areas of a tank which are deprived of oxygen (anaerobic zones) or denitrification is not taking place properly, nitrate will build up. This can also happen in an aquarium where the biological loading on the system is causing an imbalance e.g is there is excessive livestock for the aquarium volume or over feeding is occurring.
The build up of nitrate can result in unwanted algae growth and the slowing down of coral growth. The nitrate concentration in a reef aquarium should be lower than 1 mg/L, although fish only aquariums would usually have a higher concentration.
Just as with nitrite, many nitrate test kits are prone to amine interference which can make the levels of nitrate appear much lower than they actually are. The Salifert test kit does not suffer from such interference and gives accurate and quick results with a total testing time of less than 3 minutes. The test kit’s range goes from a very low to a very high nitrate concentration (approx. 0.2 – 100 mg/L as total nitrate).