Basics Cycling in Saltwater Aquarium

Cycling is generally defined as starting or rebalancing the nitrogen cycle in an aquarium. Fish waste is basically composed of ammonia. This chemical, even in very low concentrations, is very harmful to your fish. Exposure to ammonia damages your fish's gills, inhibits oxygenation of its blood and, eventually, will cause weakness then death. With a lot of fishes in the sea (not to mention other organisms that produce ammonia) in the sea, one might wonder why they do not get poisoned.

Without help, keeping ammonia levels in your aquarium will prove to be a complicated and rather expensive job. Fortunately, you do have help. Naturally occurring heterotrophic (waste-eating) bacteria are present in practically every aquarium. They are nature's natural balancing mechanism. They break down ammonia to other nontoxic chemicals. This process is called the nitrogen cycle and is very important in every niche. Harnessing this process is generally called cycling.

To cycle your aquarium effectively, it helps a lot to know and understand the nitrogen cycle, the nitrification process and how you can best work with it.

In a typical tank, ammonia is released by fishes or other invertebrates. This waste serves as food for heterotrophic bacteria Nitrosomonas which converts ammonia (NH3) to nitrite (NO2). Nitrite is just about as poisonous to fish as ammonia but this chemical does not last long in an aquarium (except in isolated cases). We owe this to Nitrobacter, another heterotrophic bacterium. It consumes nitrite and converts it to nitrate (NO3). Nitrate is quite harmless to fishes and other marine animals. The only problem with nitrate is that it is fertilizer for plants - and algae. Nevertheless, because of these two helpful bacteria, your fish does not get poisoned.

In most cases, however, ammonia and nitrite levels will still rise warranting the need for cycling.

Unfortunately, Nitrosomonas and Nitrobacter multiply quite slowly at first and sometimes, external intervention will be needed to bring down ammonia and nitrite levels in your tank. To help these heterotrophic bacteria, let us look into the nitrification process further.

The nitrification process's rate in the best of times is directly proportional to the population of heterotrophic bacteria. This process involves aerobic metabolism and therefore needs oxygen to sustain it. There are different biological filters that house heterotrophic bacteria but, based on experience, the wet/dry filter is the most effective. Why is that? Because in a wet/dry filter, tank water is exposed to more air which means more oxygen will be dissolved in the water; this also follows that plants will help these bacteria process ammonia and nitrite faster. In return, heterotrophic bacteria fertilize the plants. Now that is balance!

Cedric James is a saltwater aquarium enthusiast. For more great tips about basics of cycling, visit http://www.saltwateraquariumeasy.com