Taken from Http://www.fishyforums.com
Article by Tom Ballou
The nitrogen cycle is quite possibly the most important process that happens in our aquarium, and 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. Its the key to keeping a successful aquarium, and you should understand it in order to be successful in the hobby.
Ammonia
Ammonia is basically the waste product of fish and decaying matter. Its 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, if it even lives. You want ammonia levels in your tank to be ZERO. Ways that ammonia can build up in an aquarium system include having more fish than a tank's 'biofilter' can handle, and letting things decay in the tank (rotting plants, dead animals, uneaten food).
The biofilter 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 'bioload' of your tank. The bioload 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 biofilter will not be able to keep up. Thats when ammonia starts to build up in your system and kill your fish. By stocking slowly, you allow your bacteria to grow accordingly and keep your ammonia in check.
Nitrite
When the bacteria consume the ammonia, they convert it into a less toxic substance called nitrite. While 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 syste, should be ZERO. Luckily there is another form of bacteria that consume nitrite. These bacteria appear later in the cycle. Once the ammonia eating bacteria start producing nitrite, these new bacteria begin to appear and start consuming the nitrite. Once this happens, the cycle is almost completed.
Nitrate
The final step in the '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 to 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 is generally pretty good. Many people consider levels of over 120ppm to be the point where nitrates become toxic to most fish. In any case, nitrate levels in your tank should never reach that high anyway.
Removing Nitrate
The easiest and most common way to remove nitrates from your tank is to do regular partial water changes. Many people will recommend about 20-25% of your water be changed weekly. If you have a heavy bioload (lots of messy fish) you should consider changing more. Exactly how to do a water change is beyond the scope of this article, however, i find that the 'No Spill Clean and Fill' kit by Python Products helps me alot. 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. the downside of using plants is that you must have the proper lighting for the plants to survive, which can be expensive. If the plants die, you are actually hurting yourself because decaying plants will produce ammonia. In my opinion, the best way (and the best way is usually the easiest way) to keep nitrates low is to just do regular water changes.
Conclusion
With the removal of nitrates from your aquarium, the cycle is completed. Once your tank has 'cycled', your're well on your way to having a successful hobby. Its the first step on a long and exciting road.
Article Copyright Tom Ballou 2002. Do not reproduce this article in full or in part without permission from the author.
Article by Tom Ballou
The nitrogen cycle is quite possibly the most important process that happens in our aquarium, and 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. Its the key to keeping a successful aquarium, and you should understand it in order to be successful in the hobby.
Ammonia
Ammonia is basically the waste product of fish and decaying matter. Its 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, if it even lives. You want ammonia levels in your tank to be ZERO. Ways that ammonia can build up in an aquarium system include having more fish than a tank's 'biofilter' can handle, and letting things decay in the tank (rotting plants, dead animals, uneaten food).
The biofilter 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 'bioload' of your tank. The bioload 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 biofilter will not be able to keep up. Thats when ammonia starts to build up in your system and kill your fish. By stocking slowly, you allow your bacteria to grow accordingly and keep your ammonia in check.
Nitrite
When the bacteria consume the ammonia, they convert it into a less toxic substance called nitrite. While 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 syste, should be ZERO. Luckily there is another form of bacteria that consume nitrite. These bacteria appear later in the cycle. Once the ammonia eating bacteria start producing nitrite, these new bacteria begin to appear and start consuming the nitrite. Once this happens, the cycle is almost completed.
Nitrate
The final step in the '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 to 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 is generally pretty good. Many people consider levels of over 120ppm to be the point where nitrates become toxic to most fish. In any case, nitrate levels in your tank should never reach that high anyway.
Removing Nitrate
The easiest and most common way to remove nitrates from your tank is to do regular partial water changes. Many people will recommend about 20-25% of your water be changed weekly. If you have a heavy bioload (lots of messy fish) you should consider changing more. Exactly how to do a water change is beyond the scope of this article, however, i find that the 'No Spill Clean and Fill' kit by Python Products helps me alot. 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. the downside of using plants is that you must have the proper lighting for the plants to survive, which can be expensive. If the plants die, you are actually hurting yourself because decaying plants will produce ammonia. In my opinion, the best way (and the best way is usually the easiest way) to keep nitrates low is to just do regular water changes.
Conclusion
With the removal of nitrates from your aquarium, the cycle is completed. Once your tank has 'cycled', your're well on your way to having a successful hobby. Its the first step on a long and exciting road.
Article Copyright Tom Ballou 2002. Do not reproduce this article in full or in part without permission from the author.
