Unfortunately, many people fail to properly understand the importance of the nitrogen cycle, which often results in the loss of fish during the first week or two after they set up their tank. Taking the time to understand the importance of letting your new tank cycle and knowing how to do it can save you countless hours of frustration and help keep your fish safe.
Understanding the Nitrogen Cycle
The nitrogen cycle in an aquarium is a natural chain reaction that involves various types of nitrifying bacteria. Each type of bacteria has a specific job to perform. The cycle forms when each new bacterium consumes the previous bacteria and then gives birth to the next one in the chain.
There are three components involved in this process: ammonia, nitrite, and nitrate. The entire process generally takes about 30 days. However, there is no exact time frame for it to be completed, as each aquarium is slightly different. Factors that can affect the duration of your aquarium’s cycle include the number of fish, other livestock, and the organic matter present in the tank.
When cycling your aquarium, it is extremely important to test the water regularly. This will inform you of which phase the tank is in at any given time during the process.
Phase 1 – The Ammonia Phase
Ammonia is the first component needed for the chain. Ammonia readings should be present only during the cycling process. Once ammonia begins to accumulate in the tank, the cycle will begin. Ammonia can come from fish and other livestock waste, as well as excess food and decaying organic matter from plants and animals.
Cycling the tank using live animals can be somewhat tricky. On one hand, the fish will be exposed to high levels of ammonia and nitrate, which can be highly toxic. On the other hand, you need ammonia in order for the cycling process to begin. If you plan to use fish for cycling, choose hardy, durable fish that can withstand the toxic levels during the process. They should also be relatively inexpensive. Some good options include Damsels or Chromis. While these fish tend to be plain-looking and, in some cases, can be aggressive, the good news is that they are ideal for the cycling process. Once the cycling is complete, you can either give them to someone else who’s starting a new tank or trade them in at your local pet store for more elegant fish.
Alternatively, there are other options for starting the cycling process without using fish. These include:
Using hermit crabs, which are hardy and inexpensive.
Using live sand and/or live rock, which contain living parts of the reef that will produce the waste needed.
Regardless of the system you choose, the process remains the same. Ammonia occurs in two states, depending on the pH of the water. The unionized state (NH³) is more toxic than the ionized state, as it more easily invades the body tissue of marine animals. As the pH rises, the less toxic ionized state decreases, while the more toxic unionized state increases.
Phase 2 – The Nitrite Phase
Around ten days into the cycle, nitrifying bacteria will convert ammonia into nitrite, and Nitrosomonas bacteria will begin to form. Nitrite can be toxic and harmful to fish at lower levels, but without nitrite, the cycling process cannot be completed. Nitrite levels will continue to rise until about day 25, at which point they should begin to fall.
Phase 3 – The Nitrate Phase
Once the ammonia has been converted to nitrite, the next step in the cycle is for nitrite to be converted into nitrate by Nitrobacter bacteria. This process takes time, and during this stage, the toxicity of the water is less dangerous than in the previous two stages. However, it is still important to perform regular water changes.
By taking the time to understand the importance of the nitrogen cycle, you can keep your aquarium water free from the toxic compounds that could lead to the loss of your fish too soon.
