How do you define "the cycle"?

[tperk9784]

There are so many different ideas and views on the subject. How do you define what the cycle is?

[OmarD]

Some call it the biological cycle, the nitrification process, new tank syndrome or even the start-up cycle. They all are referring to the same cycle - The Nitrogen Cycle. This very important cycle is the establishment of beneficial bacteria in the aquarium and in the filter media that will help in the conversion of ammonia to nitrite and then the conversion of nitrite to nitrates.

This process can take from 2 weeks to 2 months or longer to complete. It is vital for anyone planning on keeping an aquarium with tropical fish to understand this process. Learning about this process will help you to be successful in keeping tropical fish. The best way to monitor the nitrogen cycle is to purchase an aquarium test kit that will test for ammonia, nitrites, nitrates and ph.

Test your aquarium water every other day and write down your readings. You will first see ammonia levels rising. A few weeks or so later you should see the nitrite levels rising and the ammonia levels dropping. Finally, after a few more weeks you should see the nitrate levels rising and the nitrite levels dropping. When you no longer detect ammonia or nitrites but you can detect nitrates you can assume that it is safe to add your tropical fish.

[Travis L. Stevens]

Omar is right. There are other phases a tank will go through that are occassionally called cycles. There will be an influx of things like film algaes, hair algaes, 'pods, etc. It can take about a year for a tank to truly settle down and have everything in equilibrium. But, like Omar said, it is almost always the Nitrogen Cycle.