[ron v]

I thought I would start a thread about the persistent problem of cycling a new aquarium. Maybe ya'll could add to it and we could "sticky". Newcomers could then be referred here instead of having to explain it over and over.

Cycling is a process that all aquariums must go through before they are ready for fish. I personally am convinced that most new aquarists drop out of the hobby, in fustration, because they do not understand or respect this event. It is a biological process that normally takes place during the first four to six weeks and involves the establishment of bacteria that consume toxic ammonia and converts it into nitrite ( which is also toxic ) and ultimately into nitrate which is relatively safe.

Set your tank up with heaters filters ect. and treat water for chlorine.
To begin cycling, your tank must be supplied with a source of ammonia. There are a couple of way to do this. Probably the simplest way is to add a small fish or two. Ammonia will be produced and the cycling process is off and running. These fish will be exposed to a high level of toxic ammonia and nitrite during the cycle and should be considered expendable, in my opinion. Eventually the bacteria will develop to the point where all ammonia produced by your two fish will be converted, almost immediately into nitrate and your tank is cycled and ready to sustain those two fish. If more fish are added, more ammonia is produced and more bacteria must develop to handle the new bio-load. This is called a mini-cycle and takes place in a relatively short period of time.

You can track the process of the cycle with commercially available test kits. You will need one for ammonia, NH3, nitrite, NO2 and nitrate NO3. During the first 2-3 weeks, the ammonia will continue to rise. No nitrite or nitrate will be detected. Nitrite will then start to show up and ammonia will decrease. Eventually nitrite will decrease and nitrate will be detected. When ammonia and nitrite both drop to zero, you are done. A water change will dilute the nitrate and everyone will live happily ever after.....Except those first two fish. Ammonia and nitrite are deadly poisons and it is common for all of your starter fish to die from exposure. It is also a fact that damage to gills caused by ammonia is, to some degree, permanent even if the fish survives.

Cycling technique number two is called "fishless cycling" and involves puchasing pure ammonia and adding it to the aquarium every day. The cycle proceeds exactly the same way and can be tracked the same way with your test kits.

Set your tank up as before with heater, filter, etc. But no fish. Instead add pure ammonia until your ammonia test kit reads 3.0 ppm. Keep checking your ammonia level every day and add as necessary to keep the 3ppm. It may take several days. Nitrite will start showing up and you will need to add more and more ammonia to keep it a 3ppm. Keep adding until ammonia and nitrite both drop to zero after 24 hrs. Your nitrate will be extremely high at this point. A 90% water change will dilute the nitrate to an acceptable level. You are done and can now completely stock your tank.

The advantages of fishless cycling are numerous. First and foremost is that you don't have to sacrifice any fish. Another is that you can fully stock your tank as soon as the cycle is complete. The 3 ppm ammonia that you add each day is far more than a tank full of fish can produce, so it will be ready for more fish than you could put in. The massive dose of ammonia may also decrease the length of time for the cycle to complete.

This is an oversimplication of a complex event and I'm sure much can be added but I'm tired of typing. I would welcome your comments, and together maybe we can create something that will be of help to a new hobbyist or two.