What is Nitrate?
Put simply, nitrate is a chemical compound formed part way through the Nitrogen Cycle. The Nitrogen Cycle is the descriptive term for the process where the natural action of various species of bacteria (biological filtration) break down toxic compounds into ones of lower toxicity gradually rendering the environment safe for fishes and invertebrates. Principally, the Nitrogen Cycle involves converting the toxic chemical compound ammonia into the less toxic compound, nitrite, this in turn is converted to nitrate (not considered toxic although at high levels it may have a deleterious affect on aquarium organisms) and finally nitrate is converted to non-toxic nitrogen gas. Our concern about nitrate in the reef aquarium is that, along with phosphate, it acts as fertiliser for unwanted or pest algae and that it can also inhibit calcification in corals.
