How Do You Know When an Aquarium Is Cycled?

The nitrogen cycle of an aquarium is a biochemical process crucial to the sustainability of the ecosystem. You should never put fish or invertebrates in an aquarium that hasn’t been adequately cycled. At the same time, you shouldn’t transport fish in water that doesn’t come from an established and cycled tank. Only plants are able to withstand water that hasn’t been cycled, but only for a certain period. In fact, starting a new tank with aquatic plants is one of the first steps toward establishing and cycling an enclosed ecosystem.

What Cycling Really Means

In the fishkeeping and aquaculture world, cycling is the process of treating the water so it registers the lowest levels of ammonia, a chemical compound generated from the presence of nitrogen molecules or chains. Ammonia is toxic and can be lethal to aquarium species, thus making the practice of keeping ammonia levels as low as possible one of the most vital aspects of fishkeeping. Establishing a tank means completing the initial cycle, which in turn must be maintained as a constant.

How to Determine if a Tank Is Properly Cycled

When you dip test strips into the water, you’re checking for ammonia and nitrites, but the actual measurement mechanism looks for nitrates. To keep things simple, the test strips change colors so you can check them against a chart that comes with the kit. Some test strips are multicolored because they check other aspects of the water—such as pH, which is more important in reef tanks. However, you can keep things simple with test strips that only check for ammonia, which you should always keep as close to zero as possible. While “dip strips” (another name for litmus tests) are simple, they’re not as accurate as “titration,” or liquid drop tests.

Stages of the Nitrogen Cycle

Nitrogen is introduced through organic means such as food and plant waste. This element on its own won’t produce ammonia, but it will get there once aquarium species breathe, feed, and excrete. In an established aquarium, there will be Nitrosomonas and Nitrobacter colonies that voraciously consume ammonia, which in turn is converted into nitrites and nitrates. You only have to worry about high levels of nitrites because plants consume the remaining nitrates, hence the importance of freshwater planted aquariums. But make sure to test your aquarium for excess levels (>20 ppm) of nitrates, and rectify by doing a partial water change.

Cycling Tanks

The nitrogen cycle consists of keeping the water clean and testing for ammonia and nitrite, which will let you know the Nitrobacter colonies are sufficient to handle the bioload of the aquarium and turn the nitrites into more forgiving nitrates. You should test once a week even if you’re doing partial water changes every few days. When setting up a new tank, start off with plants and allow them to settle for a few weeks if possible. If you’re adding bottled bacteria, wait about three days before stocking the tank with hardy species. This will create a nice bacterial bloom that completes the cycle and allows more species to be introduced.

In addition to cycling your aquarium, you’ll also need several supplies to keep the tank running smoothly and its inhabitants happy and healthy. You can find everything you need at Aquatic Warehouse, a leading provider of aquarium and koi pond supplies. Stop by our store in Kearny Mesa, order your supplies from our website, or give us a call at 858-467-9297 if you have any questions.