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The Nitrogen Cycle

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What is it?

The Nitrogen Cycle is the process of establishing beneficial bacteria in an aquarium to convert amonia (e.g. your fish's poop) into nitrites and finally, into nitrates. Amonia and nitrites are harmful to fish and can cause death. Nitrates, however, is also harmful but on a lower degree. It can only be harmful in large amounts. This is why we want to cycle our tanks. Cycling a tank will provide the beneficial bacteria to convert amonia (bad) to nitrite (bad) into (nitrite) not too bad. Basically, when we perform a water change, we are just taking out the nitrites. The beneficial bacteria will live in the filter media which why it is extremely important not to wash your filter media under tap water as you will kill all of the bacteria. The cycling process generally take about a month to complete. I'd also like to advise you to buy yourself a test kit as it will be needed during the cycling process. Be sure to get the chemical, bottled test kits and not the test strips as they are known to be innacurate.

 

 

Your Ideal Water Parametres

Amonia - 0

Nitrites - 0

Nitrates - >20

 

Your Two Options To Cycle A Tank

There are three different ways to cycle a new tank. Take the time to consider which one you'd like to do.

 

Fishless Cycling

As the same suggests, this option is to cycle without fish. To cycle a tank, you need a source of amonia (like fish's poop). In this case you won't have fish to give you that source of amonia. Instead, you'll need to get yourself a bottle of amonia which should be easily found in any pet store. Fishless Cycling is generally regarded as the more humane option as you won't be killing any fish.

 

 

Cycling With Fish

Again as the name suggests, in this option, you will be cycling using fish. In this case, your source of amonia will come from the fish's poop. If you choose this option, be sure to buy hardy fish like Danios. Don't buy fish like goldfish and guppies. The fish may or many not die in the end. You can ensure their possibilty of survival throughout the cycle is high by doing daily water changes.

 

 

Image by XcepticZP, 12th July 2007. https://commons.wikimedia.org/wiki/File:Aquarium_Nitrogen_CycleZP.svg

How To Do A Fishless Cycle

 

Step 1

Setup your aquarium completely, including it being filled up with water and water conditioner as if you were going to add fish immediately. (Read my article on 'How To Setup An Aquarium' if you haven't done so already)

 

Step 2

If you're cycling a tropical tank, turn the heater up between 77 and 86 degrees. Bacteria multiplies faster in warmer water. If you're cycling a coldwater tank, the process may take a little longer but it can still be done.

 

Step 3

Take a visit to your local fish store and buy a bottle of pure amonia

 

Step 4

Add small amounts of the amonia into your tank. Test the water with your water test kit. It's best that you don't use test strips as they are generally inaccurate. Keep adding the amonia until you get a reading of 4ppm. If your reading gets over 4ppm, you can do a small water change to bring it back down.

 

Step 5

If possible, try to grab some media (filter media, gravel etc) from established tanks from family or friends. This will help speed up the cycle as the media should have beneficial bacteria on it. Don't try and get media from the local fish store as there is a chance of disease on the media. If you're unable to grab established media, its fine, just skip this step.

 

Step 6

Test the water every few days. Once the readings for amonia start dropping to 1ppm, add some more amonia to bring it back up to 4ppm.

 

Step 7

When the amonia drops again, being testing the water for nitrites. Don't get confused by nitrites and nitrates. Amonia and nitrites is whats harmful to the fish whilst nitrates isn't unless its very high (over 20).

 

Step 8

Continue adding amonia. You want the readings for it to stay at 4ppm.

 

Step 9

Test your nitrite readings. Once they've reached a high level, you can begin testing for nitrates.

 

Step 10

Once the readings for nitrite and nitrate are off the charts, do a 50% water change with water conditioner added.

 

Step 11

Continue adding amonia to keep its reading at 4ppm.  At this point in time, test the PH. If you see the readings for PH start to drop, do another 50% water change with the water conditioner added.

 

Step 12

Test your water everyday. One day, you will find that your readings for amonia and nitrite are 0 and that you'll have a lot of nitrates. This pretty much means that they cycle has completed but theres still a little more to do.

 

Step 13

Until you are ready to go out and buy fish, you'll need to continue adding amonia daily to keep the readings for it at 1ppm. This will keep the bacteria alive.

 

Step 14

The day before you add fish to the tank, turn the heater down to your fish's prefered level and do a 90% water change. 

 

Step 15

Your tank has fully cycled and its now safe to add fish. Add 2-3 fish per week if you plan on stocking a lot. Remember to acclimate your fish properly so they don't get shocked. (Read my article on 'How To Acclimate Your New Fish). (Or if you want, you can quarantine your fish which is strongly recommended. Check out my article on 'Quarantining Fish')

 

 

 

 

How To Cycle With Fish

 

Step 1

Setup your aquarium completely, including it being filled up with water and water conditioner as if you were going to add fish immediately. (Read my article on 'How To Setup An Aquarium' if you haven't done so already)

 

Step 2

Consider what 'hardy' fish you'd like to stock the tank with during the cycling process. I would reccomend you get Zebra Danios as they are small and very hardy.

 

Step 3

If you're cycling a tropical tank, raise the temperature to suit the fish you'll be cycling with. 24 degrees celsius is good for Zebra Danios.

 

Step 4

Go out to your local fish store a buy the fish that you will like to use to cycle your tank. It's best to buy only a small number of fish to reduce to possibility of the fish being intoxicated by high levels of amonia. I would reccomend 3 small Zebra Danios at the maximum if your tank is under 200 litres. You could get away with a couple more if your tank is larger than 200 litres.

 

Step 5

Acclimate your fish properly before adding them to aquarium. (Please read my article on 'How To Acclimate Your Fish').

 

Step 6

Net the fish out of the bag and put them into the aquarium. For the rest of the day, let the fish adjust to their new surroundings.

 

Step 7

The next day, feed your fish a small amount of fish food. The left over rotting food and the fish poop is what will get the cycle started. 

 

Step 8

Later that day, test your water and do a 25% water change. Record your amonia, nitrites and nitrates on a piece of paper.

 

Step 9

Repeat step 7 and step 8 for the next few weeks. Try to do a 25% water change everyday or at least every two days to ensure the fish aren't intoxicated by amonia spikes which will happen during the cycle. 

 

Step 10

After about a month's time, you would have see mixed readings on your test kit. You want to continue repeating step 7 and 8 until amonia is 0, nitrite is 0 and your nitrate levels are very high. When you get these readings, do a 75% water change to reduce the nitrate levels.

 

Step 11

Your tank is now cycled. Hopefully your fish survived the cycle and its now up to you what you want to do with them. You could could have them as part of your aquarium setup, give them to your local fish store, or give them away to friends or family.

 

Step 12

Time to stock the tank. If you plan on stocking many fish, be sure to only add 2-3 fish per week and remember to acclimate them properly. (You can read my article on 'How To Acclimate Your Fish'). (Or if you want, you can quarantine your fish which is strongly recommended. Check out my article on 'Quarantining Fish')

 

 

 

 

 

 

Be sure to get yourself a test kit.

Image from http://www.drsfostersmith.com/product/prod_display.cfm?pcatid=4452

© 2016 by Anthony 

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