What Exactly Is Cycling?

[lemond68]

I bough a new tank and I was assured I was ready to add new fish in 3-4 days. I think now that is wrong. What is tank cycling, is there a good reference article?

 

[rdd1952]

Cycling is the process of building "good" bacteria that process ammonia (from fish waste and excess food). Simply put, bacteria develop that change ammonia, which is toxic to fish, into nitrite (with and I), which is also toxic. More bacteria form to change nitrite into nitrate (with an A) which is toxic but not to the point as ammonia or nitrite. Nitrate is then removed (or lowered) via weekly water changes.

Here is an article about cycling from the TFF homepage. There are a numerous articles on the forum about cycling. Here is one of the more recent ones. I'm not big on part of the method in that thread but it has the basics. I prefer to add the ammonia to raise the level to 5 or 6 ppm and then wait on it to drop back near zero rather than adding the same amount every day. To me that method raises the level too high and prolongs the process.