Originally Posted by Mazdamarc
the tank is non planted. So basically when nitrite starts to showup on test strips and ammonia dissappears than the cycleing process is done?
No, there are three stages to the nitrification cycle.
First, ammonia will show, then as the nitrosomonas bacteria establish and multiply the ammonia (which they "eat" so to speak) will lower to zero over several days, and during this the second stage is reached where nitrite begins to show, and nitrospira bacteria will then establish and multiply to "eat" the nitrite and produce nitrate, the third stage, when you will see nitrate above zero.
Once you have zero ammonia and
nitrite for several consecutive days, the tank is cycled for the biological load (the fish, invertebrates, or whatever is producing the ammonia if fishless cycling) it contains at that point in time. If the ammonia continues at the same rate, the bacteria will remain at the same level. If ammonia increases, the bacteria will multiply accordingly; if ammonia decreases, the bacteria will die back accordingly.
Adding new fish at this point must be slow so the bacteria have time to multiply and handle the ammonia and then nitrite.