PDA

View Full Version : The Nitrogen Cycle.



flukes
Tue Aug 17, 2004, 02:58 AM
As most living creatures, fish gives off waste (liquids & solids). These waste products are broken down into ammonia (NH3), which is highly toxic. In nature the volume of water per fish is extremely high, so waste products become diluted to low concentrations. However in aquariums there is not as much water per fish and ammonia levels can become toxic in a matter of hours.

Any ammonia reading is too high for aquarium fish, especially Discus who are very sensitive to ammonia and nitrites.

In an aquarium biological bacteria is formed to convert ammonia (NH3) into nitrite (NO2-), then their is another form of bacteria too convert nitrites (NO2-) into nitrates (NO3-).

Therefore the term cycling a tank, refers too the process of establishing bacterial colonies in the filter bed converting ammonia->nitrite->nitrates.

This nitrifying bacteria is present everywhere, thus once you have ammonia in your tank it is only a matter of time before this bacteria is established in your filter bed.

When cycling an aquarium it is important that no dechlorinates are used, these products can remain in the tank and absorb any ammonia that the fish are producing, which you need to start your bacteria colony.
The most common way too start the nitrogen cycle or nitrification cycle, is too add one or two hardy fish, goldfish, zebra danios or barbs are a good starter. These starter fish will create ammonia too start the cycle. Try not too overfeed as the more food means more ammonia. Also make sure the fish you use are healthy just because they are starting the cycle doesn't mean they wont leave disease when they are taken out.

In the process of the nitrogen cycle you should have two peaks, first the ammonia should peak at about 3-5ppm, then this should drop once the bacteria has formed to convert this into nitrite. Then you will have a nitrite peak, your ammonia should only be minimal whilst in the nitrite peak. While the nitrite is peaking nitrate forming bacteria is forming and once it has formed it will then turn the nitrite into nitrate.

Once both the ammonia and nitrite levels have fallen and your nitrates have risen the cycle is over and now you must do a water change to get rid of the nitrate. After any cycle a larger water change is recommended. Too make sure you tank has completed cycling wait for 12 hours after the water change and whilst feeding the fish. Take a test for ammonia and nitrites they both should be zero, just as a precaution take a water sample too a lfs where they can test it. Some might charge a small fee.

A tank should be fully cycled in 2-6weeks compared to other bacteria nitrifying bacteria takes along time too grow, even in optimal conditions it takes 15hours to double in size.

Make sure no more than 2 fish are added till the end of the cycle, because if more fish are added this means more ammonia, levels that high can be toxic and even fatal to even the strongest fish. It is cruel if the ammonia is not kept to a reasonable level.

If when cycling the ammonia becomes to high there are a few ways to reduce it, firstly would be too do partial water changes, do small 10% water changes and check the ammonia levels between each one. Another way is too use a product like ammo-lock which reduces the amount of ammonia in the tank, you must be sure of amounts your using though as you don't want to take all of the ammonia out.

There are a few ways too speed up the cycle, One way is too add some object from a healthy established tank. An established tank will have bacteria growing on most of the tank, try and get a sponge from a tank that is established. You can either just tie the sponge to some part in the tank or you can put it in your tank, either way aslong as its in the tank with water circulating the bacteria will reproduce and spread through your tank. You can also use gravel from an established tank, take say 1 cup of gravel and hang inside of the tank in a bag or stocking. Once the cycle is over you can remove the bag. There are also products on the market that claim to contain this bacteria (cycle, Fritz, Bio-zyme). These claim to contain the bacteria needed which can than be added to your tank.

Over the net there are mixed opinions on these products, some say they work, some say they are a waste of money. I think the main reason being is that the bacteria need food and oxygen to survive, so depending on the freshness of the bottle you could have either live or dead bacteria, unfortunately many of these products do not come with a production or use by date so you don't know how old they are.

If you choose too take gravel or sponge from an established tank, make sure that the tank is healthy and clean, try to avoid store tanks which are very likely to contain unwanted pathogens (bacteria, parasites, etc.)

In conclusion cycling is a slow process, don't try to rush it as it will be the backbone of your tank for years too come.

Once you have read this and understand the nitrogen cycle try giving fishless cycling a go, information can be found =
HERE (http://www.discusforums.com/forum/viewtopic.php?t=895)