The Aquarium Nitrogen Cycle

All living creatures give off waste, fish are no exception. These waste products which are nitrogen base break down into ammonia, which naturally is highly toxic, to just about all fish. In the wild, the volume of water per fish is very high in waste products become diluted to very low concentrations. In your aquarium, however, it can take as little as a few hours for the ammonia concentrations to reach toxic levels.

So you may be asking yourself how much ammonia is too much. Well, if you have a test kit for ammonia and test your water, and you're able to measure the ammonia in it then you have too much. At that point you may want to consider doing a water change to get the ammonia levels down. But as in nature, there are ways that you can keep the ammonia level under control in your aquarium.

In your aquarium, the nitrogen cycle is the biological process that converts ammonia into relatively harmless nitrogen compounds. Several species of bacteria do this work for us. Therefore, when you hear the term -cycling the tank- this refers to the process of establishing bacterial colonies in the filter bed or gravel bed that convert ammonia into nitrates.

Now establishing the desired bacterial colony is not as hard as you may think. The nitrifying bacteria are present everywhere, so as soon as you have ammonia source in your tank is only a matter of time before the bacteria will establish a colony in your filter bed or in your gravel bed. Easiest way to do this is when you first set your tank out, place one or two inexpensive fish in your aquarium. Their wastes will produce the ammonia that the bacteria will need to feed on.

What you'll noticed when starting a cycling process is the ammonia levels will go up and then suddenly drop down as a nitrate forming bacteria do their job. Once the bacteria take hold, nitrite levels will fall and nitrate levels will rise. Once this happens, the cycling process is complete.

You will need to buy the proper test kits. To determine when the cycle has completed. The process can normally take anywhere from two to six weeks. You will know when you're aquarium is fully cycled and when the ammonia and nitrite levels are zero, and you are seeing levels of nitrates.

So that your aquarium has cycled, what next. Well now, is it time to slowly add fish to your aquarium. It is recommended that you add no more than two fish at a time to your aquarium. And allow sufficient time between the adding fish for the bacteria level to adjust to control the ammonia. This will eliminate a sudden rise in the fish waste and naturally, a sudden rise in ammonia.