Cycling, the Chemisty behind it?

[kevy]

Can anyone explain what is actually happening or know a good site that explains it? I know that the levels of nitrate and ammonia at certain points rise and fall during the cycle but I'm really interested to know why. Then how does using fish or not using fish change it?



I've been asking a lot of questions on this forum lately and I really appreciate your replies. When I get into a hobby I like to know as much as I can, and this has probably been the most helpful forum I’ve used.

 

[dolphin]

Hi kevy

Well a quick fish tank chemistry leason.

When you set up a fish tank, there are no bacteria in the filter. The fish produce ammonia from there gills and there urine, and a small amount is produced from there poo, and the uneaten food.
As there are no, or very littel bacteria to convert the ammonia, the levels soon start to rise. The ammonia acts as a source of food for the bacteria, and these soon start to colonise the surface areas within the fish tank and the filter. These bacteria convert the ammonia (NH4) to nitrite. You will then see the levels of ammonia drop to 0, and the nitrite levels start to rise. A different bacteria then starts to oxidise the nitrite to nitrate.

When the bacteria have multiplied to such levels that they can handle to continual production of ammonia, and convert it to nitrite and then nitrate the cycle process is completed. At this point it is safe to start adding more fish, but only a few at a time.

HTH

 

[kevy]

That was exactly the reply I was hoping for, thanks dolphin. If the ammonia comes from fish, how do fishless cycles work? Do you just have to wait for ammonia to build up enough for the rest of the process to start?

 

[Great Lakes]

Fish waste and other decaying matter such as uneaten food release ammonia. Then as the ammonia levels in your tank rise, natural bacteria attack it and convert it into nitrites. Then as the nitrite levels rise, another bacteria steps in to convert it into nitrates.

Ammonia and nitrites are harmful to your fish at any level. Nitrates are not.

These beneficial bacteria take over a week to establish themselves in your tank. That is why it is important not rid yourself of them while cleaning and doing water changes.

I am certain that there are still people out there that think cleaning their fish tank means puttting their fish in a bowl and scrubbing the gravel and tank out to get it real clean.

 

[Wasserpest]

For fishless cycling, you add Ammonia to a tank which will give food to those beneficial bacteria. Also, there are several products that you can add to your tank which supposedly speed up the cycling time.

If you have/want to set up a planted tank, cycling time will be reduced. There is a very nice explaination of this here: http/www.csd.net/~cgadd/aqua/art_plant_newtank.htm (only if you are interested in planted tanks!)

If not, you could also "fishless cycle" by adding a little bit fish food (flakes) to the tank, which will be a source of ammonia and food for bacteria.

I think it is important to add fishies to a new tank very, very slowly. Add only 2 or 3 at a time, then wait another two weeks, etc. Yeah, takes some discipline, but it can prevent some dead fish.

 

[kevy]

Awesome, I think i got most of the infomation I needed. Thanks