Can some1 explain to me about the nitrogen cycle, Please.

[hihello405]

I had read 4-5 articles about the nitrogen cycle. I totally understand the concept, but,

1. It first starts off with ammonia, then nitrite and nitrate. I read something like, the test kit should not detect ammonia, therefore how can the cycle start?

2. Does the cycle keep on going continuously, or it just happen when you first set up the tank?

3. It said the cycle is complete when ammonia and nitrite are zero, but nitrate is skyrocket high, do I have to get rid of nitrate or it just go away by itself.

4. Do I have to worry about the cycle at all, if I have a filter and working properly and the water is clean, changing the water every 2 weeks, does that mean I don’t have to worry about the cycle?

5. Why do we have to learn the cycle?


Are there any more important infos I need to understand, can someone please explain this to me, HELP.

[Manix]

The cycle won't start without an amm. source. You either get this by adding a fish, or adding pure amm. and fishless cyle.

The bacteria can then develop that brakes down the amm. to nitrite. Thats when you see the nitrite spike. The nitrite drops after the bacteria that brakes that down develops. Then you have your nitrates. You want these to be less than 40 ppm. You remove these via water changes.

If you understand the cycle then you can easily determine when it' safe to add fish. Also, if something goes wrong with the tank and your fish get sick, you'll need to check your water perimeters. Some meds hurt the bacteria that develop during the cycle so you will need to know how to monitor your water. For example, if your nitrite spikes afer the tank has cycled, you will need to find out why. Understanding how the cycle works can help.

[OrionGirl]

1) Ammonia levels are always present, just at levels too low for the hobbyist test kits to detect. A tank with no source for ammonia--ie, no fish, no decaying matter, will test 0. A tank that has bacteria colonies inadequate for the amount of ammonia present will have detectable levels of ammonia.

2) The 'cycle'--ammonia converted to nitrite converted to nitrate is present in any system with fish all the time. The bacteria colonies are in balance with thier food supplies, so you can't detect the toxins.

3) Nitrates are removed (diluted) with water changes, or plants (which consume nitrates and ammonia).

4) All tanks will cycle. The purpose of many filter media (sponges, bio-balls, etc) is to provide a good location for the bacteria to establish. If you do nothing more than add fish, the tank will develop these colonies, but the fish will be injured by the exposure to ammonia and nitrites in high levels. The only way to avoid the cycle is not add fish, or to do 100% water changes multiple times per day--and even then, the bacteria will grow, just in small quantities.

5) Understanding what is going on helps you provide a stable and healthy environment for fish. Ammonia and nitrites are deadly to fish in high concentrations, and burn gills and damage the fish at lower levels. If you don't understand the process, how can you maintain it's stability?

[thom336]

1) The ammonia should be converted as soon as it is produced in a well balanced aquaria.

2)The nitrogen cycle is a continuous thing, and it is going on constantly in the world all around you.

3)The cycle is never complete - and nitrate is primarily removed through water changes.

4) I wouldnt lose sleep over it. And the scenario you state is a perfectly working cycle (providing water quality remains good).

5) Its a general useful piece of information - you can now look around you and know how it all works.

[JSchmidt]

Understanding the cycle of an aquarium is helpful because it helps you understand some basic things that you'll need to do to keep your fish healthy. Many, many people give up on fishkeeping because their fish keep dieing early on from ammonia or nitrite poisoning, and a bit of knowledge of this cycle could help avoid a lot of frustration and fish deaths.

Ammonia is a waste product respired by fish thru their gills. Decaying organic matter (plants and food) also produce ammonia as they decompose. Ammonia is bad for fish -- it is toxic and burns their gill tissue. In a cycled aquarium, there are bacteria living on surfaces (on filter media and all other surfaces in the tank) that eat the ammonia, and excrete nitrite as a result. Nitrite is also toxic to fish, but a second set of bacteria consume nitrite and produce nitrate as waste. Nitrate is much less toxic (some argue that it's really not toxic except at dramatically high levels), but it serves as a measure, if nothing else, of the general buildup of pollutants in the water. Partial water changes reduce the amount of nitrates (and other pollutants in the water.) Plants will also take up nitrates; in some heavily planted tanks, nitrates have to be added to keep the plants healthy.

The cycle continues as long as their is life in the tank. Fish respire ammonia, organic matter decays, and the ammonia- and nitrite-eating bacteria do their thing. If the bioload increases, the number of bacteria increase to process the additional ammonia and nitrites. Sometimes the bioload increases faster than the ability of the bacteria to reproduce, which produces something often called a "mini-cycle": where a previously cycled tank starts showing detectable ammonia and/or nitrites. This usually happens after the addition of too many new fish or an overly vigorous cleaning of biofilter media.

After a tank is up and running and cycled, you don't need to worry too much about the cycle. It's a good idea, I think, to occasionally monitor ammonia and nitrites, just to make sure all is OK, and most of us test regularly for nitrates to help guide our water changes. I have found that, after a tank is stable for about 4 months or so (e.g., after its fully cycled, no new fish, that sort of thing) I can predict how quickly nitrates will build up. Before that time, the rate of nitrate buildup changes as the tank matures, so more frequent testing (weekly?) might be a good idea.

I am not a big fan of arbitrary 'rules of thumb' for water changes (e.g., 20% every two weeks). The amount of water that needs to be changed is really dictated by how fast the water is polluted. That rate is dependent on how often you clean filters, how many fish you have, what kind of fish you have, how much you feed them... All these variable make the arbitrary rules for water changes pretty senseless, I think. It's much simpler to just test for nitrates and try to keep them below some target, say 40 ppm. Then your making changes based on your tank's bioload and not some meaningless percentage that may or may not do the trick.

Sorry for the long reply, but you ask good questions.

Jim

[Geez! Three replies in the time it took me to write mine! I gotta start typing faster...]

[Slappy*McFish]

I'm going to just rehash some things that were discussed by the others, in my own words here.

When people refer to a "cycle" it is basically the period of time that it takes a new tank to develop and grow the bacteria colonies required to maintain the eventual bioload of the tank. The bioload is the total sum of waste produced by organics(living or dead). Usually the cycle lasts about 4-6 weeks on average, but depends on a number of things, as it can last as little as a few days up to months.

There are several ways in which to cycle a tank. You can fishless cycle by adding pure ammonia, as earlier mentioned, or you can cycle with fish. If one adds dirty filter media or gravel from an established, mature tank to the new tank, this will add billions of nitrifying bacteria to the new tank "jump starting" the cycle. Now that you have all those bacteria, you need to feed them, or they'll starve to death. This is when you would add a few fish to the tank. This is the only way I would try to cycle "with" fish in the tank, as it saves quite a bit of time for the initial bacteria populations to develop, increasing the fishes' chances for survival. During this time is when you will monitor the water levels daily until the ammonia and nitrites read zero, then you would replace about 50% of the water to reduce the build-up of all the nitrates that have accumilated throughout the cycle. You can then add some more fish(slowly, a few at a time), and allow the bacteria population to grow a little more after the addition of the newcomers.

The bacteria populations will grow as large as the food source will allow. They are greedy little buggers and will not conserve food. They live on the brink of starvation. So if you increase the bioload, you will inturn be providing more food for bacteria(and algae), causing the populations to increase. This is why it is important to have plenty of places for bacteria to colonize. They will colonize areas where the oxygen is greatest(filter, gravel surface, tank glass, rocks). You want to make sure you have more than enough filtration and space for these bacteria to grow.
Once you have reached your tank's maximum limit(fish load), and no longer plan to add any more fish, and all your water parameters read good(0 ammonia, 0 nitrites, and 0-30ppm nitrates), then you have officially completed your cycle. Now you can kick back and enjoy your fish. All you need to worry about now, is making sure you don't have any over-feeding accidents, dead fish, or over crowded conditions. Cloudy, smelly water is a sure sign that you aren't doing something right. Keeping up the necessary water changes and filter cleanings to keep the nitrates and organic buildup at safe levels is something you'll always do as long as you have your tank.

The cycle isn't something you are forced to know, but rather something you should want to know. I usually try to find out as much information I can about something I am doing or plan to do, including my aquariums. They just interest me. Some people may think all the talk of water chemistry and bacteria is boring, but it is a major part of the aquarium's ecosystem. The "backbone" so to speak. You should try to learn as much as you can, as it will make things much easier and enjoyable in the long run. Many people who quit the hobby due to frustration, simply lacked the knowledge necessary to tackle their problems.

[aquariumfishguy]

Here is an article on cycling your tank...it's easy to understand, but certainly not lacking info:

The Cycle Process (http://www.geocities.com/care4fish2002)

[hihello405]

Thank You to every one of you, you guys are great, post the replies so fast. I am saying Thank You from the bottom of my heart, thanks.

But I have several more questions to ask:
1. Understanding the cycle would help when is the right time to add fishes and when to change the water. I have goldfishes, which are really dirty fishes; therefore I have to change the water more often. When do I change the water? Do I get a nitrate test kit to test when to change water? Do I change water when the nitrate is over 40 ppm? Or close to 40 ppm?

2. When is the right time to add new fish? 1 at a time right? Do I add fish when the ammonia and nitrite are zero?

3. Which test kits should I get, should I get ammonia, nitrite and nitrate? All 3 of them? Which one will you guys recommend me to get.

4. What if ammonia is too high, that will stress the fishes, but the bacteria didn’t grow as fast as the ammonia does. Should I change the water immediately? But the ammonia hadn’t change into nitrite?

5. What if ammonia and nitrite are too high? But nitrite hadn’t change into nitrate yet?

6. What’s the safe measure for ammonia and nitrite? I know nitrate is 40 ppm.

[pinballqueen]

Originally posted by hihello405
1. Understanding the cycle would help when is the right time to add fishes and when to change the water. I have goldfishes, which are really dirty fishes; therefore I have to change the water more often. When do I change the water? Do I get a nitrate test kit to test when to change water? Do I change water when the nitrate is over 40 ppm? Or close to 40 ppm?

Before the nitrates reach the arbitrary amount, in this case 40ppm (or 20 in my case, since I am anal about water changes :D), it is good to change the water, rather than waiting until the readings reach that threshold.

2. When is the right time to add new fish? 1 at a time right? Do I add fish when the ammonia and nitrite are zero?

When adding new fish to an established aquarium (and by established I mean ammonia/nitrite at 0 with nitrates present to prove that the cycle is complete), try to add them in moderation, only a fish or two at a time, so as to not outrun the bacteria in the tank. The only exception is doing a fishless cycle, after which you can add a fair number of fish with no worries.

3. Which test kits should I get, should I get ammonia, nitrite and nitrate? All 3 of them? Which one will you guys recommend me to get.

Buy all 3 test kits if you can. I know they aren't the cheapest things in the world, but they last a long time, and you will need them, if for no other reason than troubleshooting.

4. What if ammonia is too high, that will stress the fishes, but the bacteria didn’t grow as fast as the ammonia does. Should I change the water immediately? But the ammonia hadn’t change into nitrite?

Anytime you see toxins reading in the water, a water change will be a good thing. Even if you don't see toxins in the water, water changes never hurt. Now, what you have described is referred to as a "mini-cycle" in an established tank, and just plain cycling in one that isn't established. If you choose to cycle with fish, frequent water changes are a must to prevent the ammonia from damaging or killing your pets.

5. What if ammonia and nitrite are too high? But nitrite hadn’t change into nitrate yet?

See above, but replacing "ammonia" with "ammonia and nitrites".

6. What’s the safe measure for ammonia and nitrite? I know nitrate is 40 ppm.

The only "safe" measure for ammonia and nitrite is 0. Both ammonia and nitrites are toxic in fairly small doses. (To prove my point, open a bottle of ammonia and smell of it and notice the burning sensation in your nose and throat. It doesn't take much.)

Hope this helps-

Mandy

[JSchmidt]

I usually recommend water changes to keep ammonia below 1.5 ppm and nitrites below 1 ppm when cycling with fish. You certainly don't want them to register any higher.

HTH,
Jim