| The Nitrogen Cycle explained |
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The Nitrogen Cycle is quite possibly the most important process that happens in our aquarium. We cannot physically see it except through testing our water. In short, the Nitrogen Cycle is the process by which ammonia is eventually converted into nitrate. It’s the key to keeping a successful aquarium, and you should understand it in order to be successful and enjoy the hobby of fish keeping. This article is a simplified explanation of the Nitrogen Cycle.
Ammonia - Ammonia is basically the waste product of fish and decaying matter. It’s quite toxic to fish, and can burn their gills. Even very short exposure to high levels of ammonia can damage a fish for its entire life, that is, if the fish even lives through the exposure. You want ammonia levels in your tank to be ZERO. Ammonia can build up in an aquarium system in several ways. The two main causes are:
· having more fish than a tank's 'bio-filter' can handle.
· letting things decay in the tank (rotting plants, dead animals, uneaten food).
The bio-filter is the population of bacteria in your tank that consume ammonia and convert it into less toxic substances. The size of this population of bacteria is in proportion to the 'bio-load' of your tank. The bio-load is how much waste your fish produce. The thing you must remember when stocking your tank is that you need to stock it slowly to let the bacteria grow to keep up with the ammonia. If you stock too quickly, the bio-filter will not be able to keep up. If the bio-filter can not keep up, that’s when ammonia starts to build up in your system and may lead to the death of your fish. By stocking slowly, you allow your bacteria to grow accordingly and keep your ammonia levels in check.
Nitrite - As bacteria consumes the ammonia, they convert it into a less toxic substance called nitrite. While nitrites are not as damaging as ammonia, nitrite can also hurt your fish if its levels in the aquarium are too high. Ideally, nitrite levels in your system should be ZERO. Luckily there is another form of bacteria which develops in your tank that consumes nitrite. These bacteria appear later in the Nitrogen Cycle. Once the ammonia eating bacteria start producing nitrite, the new nitrite consuming bacteria begin to appear. Once this happens, the cycle is almost completed.
Nitrate- The final step in the Nitrogen Cycle is the conversion of nitrIte to nitrAte. Nitrate is considered to be much less toxic than nitrite, but if levels in the aquarium become too high, they can also prove to be damaging. Since there are no bacteria that consume nitrate and convert it into something else, we must deal with nitrate in other ways. Keeping your nitrates at zero can prove to be a very difficult task. While a good aquarium system should have ammonia and nitrite readings of absolutely ZERO, a nitrate reading of 30ppm (ppm = parts per million) is generally pretty good. Many people consider levels of over 120ppm to be the point where nitrates become toxic to most fish
Removing Nitrate - The easiest and most common way to remove nitrates from your tank is to do regular partial water changes. Many experienced fish hobbyists will recommend about 10-25% change of your water once or twice a month. If you have a heavy bio-load (lots of messy fish) you should consider changing the water more often. Exactly how to do a water change is beyond the scope of this article, however, at Pet Traders we find that the 'No Spill Clean and Fill' kit by Python Products helps out a lot. Another way to lower nitrate levels is to add live plants to your aquarium. Nitrate is a natural fertilizer for plants, and they consume it. Plants also oxygenate the water providing a healthier environment for your fish. It is important to note that to keep live plants in an aquarium you must have the proper lighting for the plants to survive. Generally the rule of thumb is 2 to 4 watts per gallon. If the plants die and you do not remove them, you are actually hurting yourself because decaying plants will produce ammonia.
Conclusion - Once nitrates are being removed from your aquarium, the ‘cycle’ is complete. Once your tank has 'cycled', you’re well on your way to having a successful aquarium and an enjoyable hobby. It’s the first step on a long and exciting road.
*This article is based on an article written by Tom Ballou.