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What is 'Cycling'? - Beginners, read!


Azedenkae

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Well, recently I've come across many that seemed to not fully understand what is 'cycling', or rather, what is it truly for. I find that it makes it harder for people to do the right thing from the beginning. So, I decided to do a write-up on 'cycling'. I find that especially nowadays, the true goal of 'cycling' is lost on many beginners, as the focus is too much on the ammonia, nitrite and nitrate readings, rather than what 'cycling' is actually for. :) Hopefully this will provide some useful information. :)

 

http://sosofishy.blogspot.com.au/2014/11/what-is-cycling.html

 

It's my own blogpost. I am not sure how to format it on here as a post, so there's the link. :P

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One of my biggest pet peeves is how we use the word cycle. The word cycle is short for nitrogen cycle; but it is common and accepted practice to use it synonymously with an ammonia spike. While an established nitrogen cycle (cycle) is desirable, an ammonia spike (cycle) is not.

 

Ammonia spikes are common when the cycle is becoming established. They are caused by insufficient nitrifying bacteria (which convert ammonia to nitrite, and further into nitrate) to keep up with the ammonia that is being produced by bacteria that supports ammonification (the process of breaking down organics into ammonia).

 

And while they are most common when first setting up an aquarium, an ammonia spike can occur whenever there is more ammonification than nitrification. But since the bacteria populations adjust to their energy source, the nitrifying bacteria populations will eventually adjust to the new parameters (provided there is enough hard surface area for them to colonize).

 

These "mini cycles" are just ammonia spikes caused by the sudden increase (sometimes temporary) in organics available to be broken down. This can be caused by increasing the bio-load (like adding new fish), the death of a fish or other relatively large creature, adding uncured live rock or sand, or releasing trapped organics by disturbing a mature sand bed.

 

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One of my biggest pet peeves is how we use the word cycle. The word cycle is short for nitrogen cycle; but it is common and accepted practice to use it synonymously with an ammonia spike. While an established nitrogen cycle (cycle) is desirable, an ammonia spike (cycle) is not.

 

Ammonia spikes are common when the cycle is becoming established. They are caused by insufficient nitrifying bacteria (which convert ammonia to nitrite, and further into nitrate) to keep up with the ammonia that is being produced by bacteria that supports ammonification (the process of breaking down organics into ammonia).

 

And while they are most common when first setting up an aquarium, an ammonia spike can occur whenever there is more ammonification than nitrification. But since the bacteria populations adjust to their energy source, the nitrifying bacteria populations will eventually adjust to the new parameters (provided there is enough hard surface area for them to colonize).

 

These "mini cycles" are just ammonia spikes caused by the sudden increase (sometimes temporary) in organics available to be broken down. This can be caused by increasing the bio-load (like adding new fish), the death of a fish or other relatively large creature, adding uncured live rock or sand, or releasing trapped organics by disturbing a mature sand bed.

 

 

That is definitely true, and is definitely why I had to clearly define 'cycling' in the blog post very clearly. I think we can both agree that 'cycling' is more so about controlling the bacterial population/composition, than about the actual nitrogen cycle itself.

 

In the end, cycling is about establishing enough bacteria to break down the inorganic molecules at each point, which like you said, can happen any time, and may simply consist of the alteration of the population structure, rather than a massive increase in bacteria for example.

 

I would rather a more precise term, but as with many terms used in the hobby, it has become the 'norm' and so rather hard to change. :/ But well, at least hopefully through this people understand more of what the term actually means in reality, and therefore what to do, as opposed to being confused.

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So I may be Captain Obvious, but...

 

Going Slow (Adding anything that requires food) is for the the bacteria population to have a chance to grow and meet the needs of your system.

 

Example;

1) New Tank, Nitrogen Cycle Complete; There is enough bacteria to support the current system.

2) Add a Fish, Small Cycle; As you add food/fish waste, the Bacteria Population needs to grow to stabilize the new incoming Nutrients for export.

2.1) The more (Quantity) you introduce at once, the higher nutrients you are adding. The bigger/longer the mini cycle will take until the Bacteria Population grows large enough to support the new incoming nutrients.

 

Please Correct me if I am wrong, but this only applies to Fish/Coral that you are going to Feed? Example; Softies and Some LPS are photosynthetic and do not require feeding.

 

T.

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I'm not trying to correct you. I'm just trying to add to the discussion. Hopefully it helps someone else understand it a little better.

 

That is definitely true, and is definitely why I had to clearly define 'cycling' in the blog post very clearly. I think we can both agree that 'cycling' is more so about controlling the bacterial population/composition, than about the actual nitrogen cycle itself.

 

In the end, cycling is about establishing enough bacteria to break down the inorganic molecules at each point, which like you said, can happen any time, and may simply consist of the alteration of the population structure, rather than a massive increase in bacteria for example.

IDK that we're really controlling the populations; they basically self regulate. Sure you can introduce bacteria cultures and dose ammonia; but even if you don't, the nitrogen cycle will still become established for the existing bio-load. When first starting out, this only consists of the life on the live rock and sand. If, however, there was a lot of die off on the live rock, the bacteria populations might be elevated due to the larger source of energy.

 

I would rather a more precise term, but as with many terms used in the hobby, it has become the 'norm' and so rather hard to change. :/ But well, at least hopefully through this people understand more of what the term actually means in reality, and therefore what to do, as opposed to being confused.

I agree about the confusion and try to use "ammonia spike" instead of "cycle" whenever appropriate. I'm OK with "cycling" or "to cycle" being used to describe establishing a biological filter (via the nitrogen cycle), although I often try to clarify it in beginner's posts.

For example: The cycle doesn't end (an ammonia spike ends), while the cycle eventually becomes established/balanced for the current bio-load.

 

Although some people find it a little too nit picky.

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Add a Fish, Small Cycle; As you add food/fish waste, the Bacteria Population needs to grow to stabilize the new incoming Nutrients for export.

It depends on how large of a percentage you have increased the bio-load. Given enough live rock, the bio-filter can often handle the increase without an ammonia spike. We usually try to increase it very gradually (like adding a cleanup crew first). However, if you are using dry rock and add a fish, then your tank will likely experience an ammonia spike.

 

Please Correct me if I am wrong, but this only applies to Fish/Coral that you are going to Feed? Example; Softies and Some LPS are photosynthetic and do not require feeding.

Yeah (even though many soft corals can feed), that's generally how I define what adds to the bio-load of a tank. Although they will have minor effects on the nitrogen cycle, they generally don't produce a lot of ammonia (unless part of the colony dies).
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So I may be Captain Obvious, but...

 

Going Slow (Adding anything that requires food) is for the the bacteria population to have a chance to grow and meet the needs of your system.

 

Example;

1) New Tank, Nitrogen Cycle Complete; There is enough bacteria to support the current system.

2) Add a Fish, Small Cycle; As you add food/fish waste, the Bacteria Population needs to grow to stabilize the new incoming Nutrients for export.

2.1) The more (Quantity) you introduce at once, the higher nutrients you are adding. The bigger/longer the mini cycle will take until the Bacteria Population grows large enough to support the new incoming nutrients.

 

Please Correct me if I am wrong, but this only applies to Fish/Coral that you are going to Feed? Example; Softies and Some LPS are photosynthetic and do not require feeding.

 

T.

 

I hate to say, but that's not quite right.

 

See, if the cycle is done right, then you can and should be adding live stock quite quickly, and early on as well.

 

The purpose of the cycle is to cultivate a large amount of bacteria, essentially establishing a highly efficient biological filtration system. Gee I really hate the term 'cycle' now. Let's call it 'bacterial propagation phase'. Or BPP.

 

So during the BPP, what you are looking to do is establish enough bacteria to handle your live stock, which means that once the BPP is over, you should be able to add most of your live stock right away. This is of course more beneficial for both you and the live stock (especially the live stock), as all the fish and everything can get used to each other right away.

 

Most people don't go through the BPP properly (technically they do, as they do grow some bacteria that breaks down waste), but it is only a small proportion of what they should grow. Therefore, rather than having enough bacteria from the getgo, they have to add one fish or coral or whatever at a time, growing a bit more bacteria each time. This takes months, and poses a danger if anything do go wrong. It is unfortunate as people tend to misunderstand the purpose of the BPP, looking just at an increase then decrease of waste products as an indication, not caring so much about how much of an increase it is, or testing what sort of bioload the bacteria can take.

 

So the process should be more:

1.) Grow a massive amount of bacteria, a lot more than 'necessary' probably.

2.) Add in live stock as wished.

 

The large amount of bacteria will handle the waste produced from the addition of live stock, if done right. And it should not be hard to be done right.

 

Hope that helps! :)

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I'm not trying to correct you. I'm just trying to add to the discussion. Hopefully it helps someone else understand it a little better.

 

IDK that we're really controlling the populations; they basically self regulate. Sure you can introduce bacteria cultures and dose ammonia; but even if you don't, the nitrogen cycle will still become established for the existing bio-load. When first starting out, this only consists of the life on the live rock and sand. If, however, there was a lot of die off on the live rock, the bacteria populations might be elevated due to the larger source of energy.

 

I agree about the confusion and try to use "ammonia spike" instead of "cycle" whenever appropriate. I'm OK with "cycling" or "to cycle" being used to describe establishing a biological filter (via the nitrogen cycle), although I often try to clarify it in beginner's posts.

For example: The cycle doesn't end (an ammonia spike ends), while the cycle eventually becomes established/balanced for the current bio-load.

 

Although some people find it a little too nit picky.

 

Well yes, they grow how they want, but we do control their growth (indirectly) by varying how much food we provide them or take away, and how much housing is available for them. Also how much bacteria is added. Not quite in terms of exact numbers, but it is easy to be sure that we are adding plenty.

 

The initial bioload (let's assume a 'barren' tank, i.e. dry rock and sand, etc.) is not enough to take on a large bioload, and that is why feeding it is necessary. And that's not just through provision of ammonia, but of chemicals that later becomes the building blocks of life. Like you said, if there is die-off, then there could be massive growth of bacteria. When there isn't, then we need to simulate that die-off. Even if there is, I tend to suggest just adding in food anyways. No harm in introducing more bacteria.

 

But yes, to be honest I dislike the word 'cycle'. Technically every time we feed, we are 'cycling' the tank, based on most people's definitions. Why? Well, we are adding in things that breaks down into ammonia and a bunch of organic and inorganic molecules. The ammonia is converted to nitrites, then nitrates, then nitrogen if lucky. So that is the nitrogen cycle happening right then and there. But really that's different from what people describe as a 'cycle' when they add new fish.

 

For many, that's when their bacterial population has to grow to adapt to more waste products being produced. But of course, if cycled correctly from the beginning, that's not an issue so long as the bacterial population is maintained, which they will be for a while. If a tank has been running for a while under the same routine, then if bacteria populations are higher than necessary, competition and lack of food will 'thin out the herd' naturally, and hence only then would a BPP be required, to increase the bacterial load.

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The initial bioload (let's assume a 'barren' tank, i.e. dry rock and sand, etc.) is not enough to take on a large bioload, and that is why feeding it is necessary. And that's not just through provision of ammonia, but of chemicals that later becomes the building blocks of life. Like you said, if there is die-off, then there could be massive growth of bacteria. When there isn't, then we need to simulate that die-off. Even if there is, I tend to suggest just adding in food anyways. No harm in introducing more bacteria.

I guess we disagree on the importance of feeding a tank before livestock is added. Adding food is like adding a dead piece of shrimp to kick start the process. Sure it works, but it encourages growth of decomposing bacteria and inputs phosphate with other potentially problematic elements (as well as ammonia) into the system.

 

However, if the point is to add livestock quickly, I agree that the nitrifying bacteria needs to be built up beyond supporting just the current bio-load (which is virtually nonexistent when using dry rock). The only energy source required to support nitrifying bacteria is ammonia. And while I don't recommend dosing ammonia in a tank that has been setup with live rock (as it can be detrimental to the non-bacterial life forms on the rock), it can be very beneficial when establishing a tank with dry rock.

 

I don't propose that what what you describe is wrong, as there are many ways to establish a working biological filter. These include transferring a working bio-filter into a system (like is often done for temporary quarantine tanks), introducing living bacteria cultures (like Dr.Tim's One & Only), feeding a tank (like you are suggesting), dosing pure ammonia (like Dr.Tim's Ammonium), using a hardy fish (like a Damsel), or using fully cured live rock and slowly adding livestock to allow the bacteria populations to keep up with the changes to the bio-load.

 

That last method has become the most common; however, with the recent popularity in using dry rock (for various reasons), adjustments have been made to build up the bacteria on the surface of the dry rock prior to adding livestock. I feel that the only "wrong" way is subjecting livestock (and even live rock) to potentially harmful levels of ammonia. This includes using a hardy fish to induce an ammonia spike.

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I guess we disagree on the importance of feeding a tank before livestock is added. Adding food is like adding a dead piece of shrimp to kick start the process. Sure it works, but it encourages growth of decomposing bacteria and inputs phosphate with other potentially problematic elements (as well as ammonia) into the system.

 

However, if the point is to add livestock quickly, I agree that the nitrifying bacteria needs to be built up beyond supporting just the current bio-load (which is virtually nonexistent when using dry rock). The only energy source required to support nitrifying bacteria is ammonia. And while I don't recommend dosing ammonia in a tank that has been setup with live rock (as it can be detrimental to the non-bacterial life forms on the rock), it can be very beneficial when establishing a tank with dry rock.

 

I don't propose that what what you describe is wrong, as there are many ways to establish a working biological filter. These include transferring a working bio-filter into a system (like is often done for temporary quarantine tanks), introducing living bacteria cultures (like Dr.Tim's One & Only), feeding a tank (like you are suggesting), dosing pure ammonia (like Dr.Tim's Ammonium), using a hardy fish (like a Damsel), or using fully cured live rock and slowly adding livestock to allow the bacteria populations to keep up with the changes to the bio-load.

 

That last method has become the most common; however, with the recent popularity in using dry rock (for various reasons), adjustments have been made to build up the bacteria on the surface of the dry rock prior to adding livestock. I feel that the only "wrong" way is subjecting livestock (and even live rock) to potentially harmful levels of ammonia. This includes using a hardy fish to induce an ammonia spike.

 

Yeah I do think we are disagreeing on the methodologies here - or perhaps the ultimate goal, and what can be sacrificed on the way. :)

 

I would say that we actually do want to encourage the growth of decomposing bacteria and bacteria that breaks down whatever else is in the water, such as phosphates and ammonia. They all become a part of the diet of some sort of bacteria, and I would personally encourage producing all this initially, to generate more of such bacteria. In general whatever can capitalize on the resources at hand best will win out, and so if we have plenty of ammonia, phosphate, nitrate, nitrite, organics and whatever else from foodstuff and that promotes growth of bacteria that can use all of that, then all the better. As when we do feed later on, it'll be the same stuff released. Except then we'll have the exact bacteria needed to break all it down. :D

 

You do make a good point though, that excessive amounts of chemicals produced can be detrimental to non-bacterial life, which can obviously be uncool. Not something that I have thought of, or had to face really. Most don't quite care at that stage, but yeah, for those who do care, it'd be a different story.

 

I do know of the slowly-adding-fish-later method, though in general I find that its common usage odd, as people are using that method even when they start bare. But anyways.

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I would say that we actually do want to encourage the growth of decomposing bacteria and bacteria that breaks down whatever else is in the water, such as phosphates and ammonia.

Unfortunately, bacteria does not break down phosphate (or some of the other residuals from decomposing matter). However, most of these can be easily removed by changing out the water before adding livestock. The method you are describing has been successfully used for a long time. But since this is a post directed at beginners, I'm just pointing out that it is not the only method that works.

 

While we might not be in total agreement on the methodology, I appreciate the time it took to put together your article. It should help a number new members better understand the nitrogen cycle.

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Unfortunately, bacteria does not break down phosphate (or some of the other residuals from decomposing matter). However, most of these can be easily removed by changing out the water before adding livestock. The method you are describing has been successfully used for a long time. But since this is a post directed at beginners, I'm just pointing out that it is not the only method that works.

 

While we might not be in total agreement on the methodology, I appreciate the time it took to put together your article. It should help a number new members better understand the nitrogen cycle.

Actually, bacteria do break down phosphates. And pretty much anything that an organism constitutes of. So urea and all that as well.

 

To be honest whilst the post did mention a method, it was more so on the importance of growing bacteria, enough to deal with the eventual bioload. And how that bacteria can deal with any sort of organic input.

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Actually, bacteria do break down phosphates. And pretty much anything that an organism constitutes of.

If you mean they can break down matter that contains organic phosphate (which is much less likely to be utilized by algae) leaving inorganic phosphate (which is much more likely to be utilized by algae, and is why people run GFO reactors), then I agree. Sure all cells utilize phosphate in some form to function; but I will agree to disagree that bacteria in our reef aquaria processes inorganic phosphate into some sort of harmless substance like nitrogen gas. If that were true, we'd be able to dose phosphate in order to build up bacteria populations that process it; but I wouldn't recommend that.
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If you mean they can break down matter that contains organic phosphate (which is much less likely to be utilized by algae) leaving inorganic phosphate (which is much more likely to be utilized by algae, and is why people run GFO reactors), then I agree. Sure all cells utilize phosphate in some form to function; but I will agree to disagree that bacteria in our reef aquaria processes inorganic phosphate into some sort of harmless substance like nitrogen gas. If that were true, we'd be able to dose phosphate in order to build up bacteria populations that process it; but I wouldn't recommend that.

Oops, my total bad. I actually was supposed yo write 'inorganic-phosphate-sequestering bacteria'. Basically those (which is quite a number) that incorporate inorganic phosphate with ADP to form ATP (energy storing). So the phosphate doesn't get reduced, it gets stored away when ADP or ATP is created, and stuff.

 

[EDIT]

 

Although there are actually those than break phosphate down into phosphorous (over a few steps). They are rarer though.

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just curious.... this is my first small tank.... is this process going be shorter or longer than a large tank? 8gal, live and and live rock? do you all recommend a water change before or after adding the livestock?

 

i know we did not do this process correctly with our large tank....

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just curious.... this is my first small tank.... is this process going be shorter or longer than a large tank? 8gal, live and and live rock? do you all recommend a water change before or after adding the livestock?

 

i know we did not do this process correctly with our large tank....

 

Depends on your rock, sand, etc for how long the cycle will take... You'll want to do a weekly water change with an 8 gallon tank. Somewhere between 10-20%, unless your NirtrAtes are high. If this is the case, you'll want to do a larger change.

 

As long as your levels are good, it shouldn't matter if you do a water change before or after adding livestock. You can just time it with your weekly water change.

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Depends on your rock, sand, etc for how long the cycle will take... You'll want to do a weekly water change with an 8 gallon tank. Somewhere between 10-20%, unless your NirtrAtes are high. If this is the case, you'll want to do a larger change.

 

As long as your levels are good, it shouldn't matter if you do a water change before or after adding livestock. You can just time it with your weekly water change.

 

ok thanks!

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ok thanks!

 

NP! Also, don't do any water changes while your tank is cycling. You should still do daily top offs with RO/DI or Distilled water though, to keep your salinity consistent.

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NP! Also, don't do any water changes while your tank is cycling. You should still do daily top offs with RO/DI or Distilled water though, to keep your salinity consistent.

 

ok, so i know its done when? nitrates are 0?

 

we never did this w our first one lol we took a sample to the lfs and they said its good before we got fish.... we didnt test ourselves....

 

can anyone recommend a good but not too expensive test kit? we used the strips on out fish only tank but if your off by 30 seconds your results are wrong... not buying them again lol

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ok, so i know its done when? nitrates are 0?

 

we never did this w our first one lol we took a sample to the lfs and they said its good before we got fish.... we didnt test ourselves....

 

can anyone recommend a good but not too expensive test kit? we used the strips on out fish only tank but if your off by 30 seconds your results are wrong... not buying them again lol

 

I think most people use the API test kits (you can buy on Amazon). Your cycle will be complete when your Ammonia and Nitrites read 0ppm. You may still have Nitrates, but anything under 40ppm is really not a big deal.

 

If you do have much higher Nitrates, while your Ammonia and Nitrites read 0ppm, you should do a relatively large water change (a 50% water change will reduce your Nitrates by 50%).

 

You'll also want to test your PH as well (part of the API kit). You'll also need a hydrometer or refractometer to make sure your salinity level is constant (should be 1.025-1.026).

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I think most people use the API test kits (you can buy on Amazon). Your cycle will be complete when your Ammonia and Nitrites read 0ppm. You may still have Nitrates, but anything under 40ppm is really not a big deal.

 

If you do have much higher Nitrates, while your Ammonia and Nitrites read 0ppm, you should do a relatively large water change (a 50% water change will reduce your Nitrates by 50%).

 

You'll also want to test your PH as well (part of the API kit). You'll also need a hydrometer or refractometer to make sure your salinity level is constant (should be 1.025-1.026).

 

ok thats what i thought! thank you so much! id rather know before i start than after a disaster LOL

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ok thats what i thought! thank you so much! id rather know before i start than after a disaster LOL

 

NP!

 

Make sure you do your research or you'll be out a lot of money. There are TONS of threads in this site that discuss the Nitrogen Cycle, testing for levels, when to add livestock, etc.... Read Read Read!

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just curious.... this is my first small tank.... is this process going be shorter or longer than a large tank? 8gal, live and and live rock? do you all recommend a water change before or after adding the livestock?

 

i know we did not do this process correctly with our large tank....

In theory cycling a larger tank takes no longer or shorter than a smaller tank. You just have to adjust dosages accordingly.

 

My article did discuss water changes, and there's another on what type of equipment should be on/off during cycling. :)

 

If you use good biological filter media that allows for nitrate-reducing bacteria, you should in fact not do a water change even with high nitrates. Rather, let the bacteria take care of it. It's better to do it all properly from the beginning.

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