# Cycles?



## fawnika (Feb 21, 2011)

Hi everyone,
I am a new aquarium owner and I have been reading some of the posts which state something like "my aquarium just completed a cycle.....". What is a cycle?
I have had my 30 gallon tank running since Jan 1st and right now the water is clear and all of the tests for pH, ammonia, nitrates, nitrites are good. 

Thank you for answering my Dumb question!


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## majerah1 (Oct 29, 2010)

Cycling is where the beneficial bacteria build up to keep the bioload of the fish in safe levels.Its not a dumb question,and many find out about it the hard way after losing tons of fishes.

To start the cycle you will need a source of ammonia.Some here have used a pinch of fish food,other pure ammonia,and others still very hardy fish,though I dont recommend the fish route.


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## fawnika (Feb 21, 2011)

Majerah1,
Thank you.
So this is just talking about when a tank is first set up, right? No cycles after that?


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## majerah1 (Oct 29, 2010)

Initially,yes.There are things you can do to throw your tank in a mini cycle,like adding too many fish at once.Balance is the key,lol.

Try reading this:Aquarium Cycling
I though there was a write up on this site too but cant seem to find it.


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## fawnika (Feb 21, 2011)

If you put in new fish is that considered another cycle?


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## majerah1 (Oct 29, 2010)

No,Im sorry i didnt explain.The colony of bacteria you are trying to establish,is to convert the ammonia(fish waste) to a less harmful substance.Its considered a nitrogen cycle.So lets say you have a ten gallon tank.You have it cycled,where the BB(beneficial bacteria)is established.You can add fish.you want to add a few every couple weeks.By only adding a few,the bacteria will build into a bigger colony,and keep the ammonia in check.However,if you decide to throw in ten fish,the amount of fish waste produced all of a sudden,will throw the cycle off balance,leading the ammonia to be built up again until the BB can handle it.This would cause the fish stress.

SO basically if you cycle first and then slowly add a few fish at a time,you will be fine(please excuse my total lack of explanative skills)


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## Gizmo (Dec 6, 2010)

The Aquarium Nitrogen Cycle

A cycle refers to the establishment of an aquarium's nitrogen cycle, where decomposing fish waste generates ammonia, which is converted by nitrifying bacteria first into nitrite, then into nitrate. Ammonia and nitrite are toxic to fish, so if possible you should establish the nitrogen cycle BEFORE adding fish (called fishless cycling). To do this, you need to provide an artificial source of ammonia, be it rotting bio-matter like seafood or flake fish food, or straight daily dosages of pure ammonia. The idea is to have concentrations of zero ammonia, zero nitrite, and some nitrate BEFORE you add fish. Otherwise you run the risk of poisoning and killing fish.

Adding or removing fish as time goes on causes "mini cycles", where the nitrifying bacteria population swells or diminishes to handle the new bio-load. We therefore recommend adding fish slowly so as not to cause another mini cycle, replete with ammonia and nitrite spikes.

Also, buy a water testing kit! It will help you track the establishment of your aquarium's nitrogen cycle.


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## jrman83 (Jul 9, 2010)

Once the beneficial bacteria has fully developed initially, mini-cycles will occur no matter how many fish you add or at what rate. The main thing to that is how long they last. Most will occur and disappear without you knowing. I have added large numbers of fish to my tanks and expected them and I know they occured, I just never saw readings indicating it.


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## snail (Aug 6, 2010)

Mini cycles in an established tank are not usually much to worry about. The big one is when first setting up the tank. The point to remember is that the cycle does not start until you add a source of ammonia (fish or other) and then it usually lasts 4-6 weeks.


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## mehran2010 (Feb 23, 2011)

I'm in my forth week of tank set up (40 L tank) with 7 small fish (2 red-eye tetra, 2 platy and 3 guppy). I have done constant water change and water Ph is 7. Is there a way other than using water test kits to identify the end of my tank-set up cycle?


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## Gizmo (Dec 6, 2010)

mehran2010 said:


> Is there a way other than using water test kits to identify the end of my tank-set up cycle?


Not that I know of. If your fish aren't acting weird or dying, that might be an indicator.


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## jrman83 (Jul 9, 2010)

mehran2010 said:


> I'm in my forth week of tank set up (40 L tank) with 7 small fish (2 red-eye tetra, 2 platy and 3 guppy). I have done constant water change and water Ph is 7. Is there a way other than using water test kits to identify the end of my tank-set up cycle?


Wait 4 more weeks and assume it is done and over. Tests are the only true way to tell.


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## beaslbob (May 29, 2009)

fawnika said:


> Hi everyone,
> I am a new aquarium owner and I have been reading some of the posts which state something like "my aquarium just completed a cycle.....". What is a cycle?
> I have had my 30 gallon tank running since Jan 1st and right now the water is clear and all of the tests for pH, ammonia, nitrates, nitrites are good.
> 
> Thank you for answering my Dumb question!


the only dumb question is the one not asked. *old dude

Technically all the cycles (like the nitrogen cycle) IMHO are never done and continue.

that said what people worry about is the dangerous spikes that kill fish.

I start my tank with live plants and have found the ammonia->nitrIte->nitrate spikes are replaced with just an initial nitrate spike. Because live thriving plants consume the ammonia directly preventing those spikes.

But that's just me

And my .02


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## snail (Aug 6, 2010)

beaslbob said:


> Technically all the cycles (like the nitrogen cycle) IMHO are never done and continue.


 True, really you want to establish an unbroken cycle. When people refer to the tank cycling they are talking about the period of time when a cycle hasn't actually developed yet, so the cycle 'finishes' only in the sense that it becomes a cycle.


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