Nitrogen cycle, cycling, nitrification, biological cycle, startup cycle, break-in cycle – whatever you want to call it, ALL new aquarium has to undergo this process.

It is when beneficial bacteria colonies are established in your saltwater aquarium.

You will learn how it works, how long it takes to get it completed, ways you can do to cycle the saltwater aquarium and the important function the nitrogen process plays to keep a saltwater aquarium working properly.

This process can take from 2 weeks or longer, but there is no exact time frame for it to be completed as each aquarium is different.

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Factors in determining where you are in the process are how many fish or other livestock, and organic matter you have in your aquarium.

The three components that are involved are ammonia, nitrite, and nitrate. Test your water often during the process and log your readings. This will tell you what phase the aquarium is in.

The best way to monitor the nitrogen cycle is by getting a saltwater test kit that will test the three components involved in the process.

Here is an explanation of how the process works:

Nitrogen Cycle Diagram

When you have finished setting up your saltwater aquarium, you can add some hardy saltwater fish such as damsels – popular fish if you are cycling your aquarium.

Feed them regularly.

You can also use live rock if you want. Dying matter in the live rock produces the ammonia source that you need.

Ammonia level will rise rapidly because you do not have the adequate concentration of the right types of bacteria. The fish will be stressed at this point and will show other signs of discomfort such as rapid breathing. The first stage of bacteria are beginning to be established.

After a couple more days, the ammonia level will reach its peak and begins to decline. Ammonia level should read zero as the first stage bacteria will then begin to convert it into the equally toxic nitrite. Nitrite levels will begin to rise. If you have a weak fish, they may not survive this stage. Others will become show more signs of stress.

A few more weeks or so later, nitrite level will reach its peak. Your saltwater fish again will show signs of stress.

Small water changes, up to 20% can help protect the saltwater fish against toxic chemicals in the water during the nitrogen cycle.

Second stage bacteria will be present and will multiply. Nitrite level will then drop and nitrate becomes detectable.

First and second stage bacteria are now established at this point of the cycle. It can keep up with the ammonia from the fish, turning it into nitrate and then quickly converting it into nitrate.

The saltwater aquarium tank should now be fully cycled. You can now slowly start adding more livestock in your aquarium.


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