It is certainly possible to do a fishless cycle if you know what you are doing as JeremyW has stated. However, there are too many people who do not know what they are doing.
It seems that many people are using Dr Tims's ammonium chloride to cycle tanks these days. The problem is that ammonium chloride, unlike pure ammonia, is acidic. Thus, if you add too much or too often, the pH will drop below neutral which can slow down the cycle and even cause it to stall if the pH goes too low.
Ammonia is alkaline, so you do not have to worry about the pH dropping. However, it does not take much ammonia to overdose the tank, especially in smaller tanks. Many people test they water and get a test result of 5 ppm without realizing that the level might be far higher than that, but the color chart stops at 5 ppm. A teaspoon (5 ml) of ammonia in a 10 gallon tank is sufficient to raise the ammonia concentration to 40 ppm. I suspect some people subscribe to the "if a little is good, more is better" approach. However, high levels of ammonia are just going to stall the process. We have encountered too many people whose cycles have stalled only to have them complete successfully after doing several water changes to bring the ammonia concentration back to a suitable range.
It seems that many people are using Dr Tims's ammonium chloride to cycle tanks these days. The problem is that ammonium chloride, unlike pure ammonia, is acidic. Thus, if you add too much or too often, the pH will drop below neutral which can slow down the cycle and even cause it to stall if the pH goes too low.
Ammonia is alkaline, so you do not have to worry about the pH dropping. However, it does not take much ammonia to overdose the tank, especially in smaller tanks. Many people test they water and get a test result of 5 ppm without realizing that the level might be far higher than that, but the color chart stops at 5 ppm. A teaspoon (5 ml) of ammonia in a 10 gallon tank is sufficient to raise the ammonia concentration to 40 ppm. I suspect some people subscribe to the "if a little is good, more is better" approach. However, high levels of ammonia are just going to stall the process. We have encountered too many people whose cycles have stalled only to have them complete successfully after doing several water changes to bring the ammonia concentration back to a suitable range.
