Understanding the Nitrogen Cycle is an important part of keeping and maintaining aquariums. When we talk about the the nitrogen cycle we are describing what happens in an aquarium as beneficial bacteria process fish waste to convert it into its least harmful form. There are three nitrogenous compounds that track the quality the water. They are ammonia, nitrite, and nitrate.
Ammonia (NH4) is the most toxic and seems to become harmful at about 1ppm.
Nitrite (NO2) is less toxic than ammonia but seems to start becoming harmful at around 3ppm
Nitrate(NO3) is even less toxic than both ammonia and nitrite but is still harmful in large quantities over long periods of time.
Our end goal is to be able to create a safe and healthy environment for the fish in our care. We do this by “cycling” before adding fish to the tank. Once the cycle is completed your tank is considered “cycled” and is safe to slowly add new fish until it hits capacity. A tank is “cycled” when ammonia and nitrite test at 0ppm and nitrate is being produced. Usually the cycle is maintained with ammonia produced from fish residing in the aquarium. It can be maintained with artificial ammonia like ammonia chloride. A cycle can be maintained for up to about two weeks without an ammonia source.
When fish go to the bathroom they produce ammonia.
This is its most harmful form and ideally is only present in the aquarium during the initial cycling. In a well balanced system ammonia should always test at 0ppm because it is instantly processed by beneficial bacteria into nitrite. Nitrite, like
As aquarists we want to create a safe environment for our fish. We are able to do this
Removing nitrate is one of the main reasons that we need to do water changes.