The Nitrogen Cycle Explained (Simply!)

If you learn only one thing in the aquarium hobby, make it the nitrogen cycle. A cycled tank is a healthy tank. An uncycled tank is a recipe for disaster.

What is it?

In short, it's nature's filtration system. Fish produce waste (ammonia), which is toxic. Beneficial bacteria convert that ammonia into nitrite (also toxic). A second type of beneficial bacteria then converts the nitrite into nitrate (much less toxic), which plants can use as food.

How to Cycle a Tank

This process is called "cycling." You need to establish a colony of these beneficial bacteria in your filter media. You can do this by adding an ammonia source (like a pinch of fish food or pure ammonia) to your new tank and waiting. It can take 2-6 weeks. You'll need a water testing kit to monitor ammonia, nitrite, and nitrate levels. When ammonia and nitrite consistently read zero, and you have some nitrates, your tank is cycled and ready for fish!