First of all I disagree with doing water changes during the cycle, only after the cycle is complete should you do a water change.
The nitrogen cycle is a chain reaction resulting in the birth of various types of nitrifying bacterias, each with their own job to do. Each new bacteria born consumes the previous one, and in turn gives birth to the next bacteria. The three components involved to make this happen are ammonia (NH3 or NH3+4), nitrites (NO2), and nitrates (NO3). The "cycle" begins when bacteria converts fish waste, excess aquarium food or other organic matter into ammonia. The ammonia is converted to nitrites by nitrifying bacteria, nitrosomonas. Nitrites are then converted to nitrates by another nitrifying bacteria, nitrobacters, which are the good kind of bacteria you want in the end. In general the nitrogen cycling process usually takes about 30 days or more, but there is no exact time frame for this process to complete its task, as each aquarium is different. Factors such as how many fish or other marine animals and how much organic matter is in the tank can vary the completion time, one way or the other. Testing your aquarium water during cycling is very important, as this will tell you what phase the aquarium is in at any given time throughout the process.
The Three Components & Phases
Phase One - Ammonia (NH3 or NH3+4)
The first component needed in the chain is ammonia, and it is only during the cycling process that ammonia readings should be present in an aquarium. Once ammonia begins to accumulate in the aquarium the process begins. So, where do you get the ammonia from? Any time you add live animals, live rock, or organic matter to an aquarium, ammonia will result. Putting live animals into a tank for the purpose of cycling is not easy, because they are exposed to highly toxic levels of ammonia and nitrities during the process, but without ammonia present the cycle cannot begin. If ammonia is removed, or the supply is disrupted during cycling, the process stops. As you see the ammonia level rise during the cycling period, if you think by adding an ammonia destroyer or doing a water change to bring it down is helping, it doesn't! You are only delaying the cycling process and preventing it from completing its mission. If you use fish to cycle an aquarium, it's a catch 22! You don't want to put the animals in harms way by exposing them to toxic elements, but you need their waste as the ammonia source to get the job done. This can also be done by using a dead raw shrimp which I prefer as a cycle method.
Hope that explans it.
Thomas
9 fish in a 55 is also a bit much. Everything still alive? That ammonia is deadly and at that level you could loose some fish.
