can say this in my sleep now and probably often do.
when cycling a tank ammonia is created naturally or added. it can be created by using fish to start the cycle which is stressful on the fish. or added by purchasing ammonia and adding it to tap water in the tank. has to be 100% pure ammonia. ammonia is created by excess food, fish waste and decaying matter left in the tank. ammonia is broken down to nitrites , which are then in turn broken down to nitrates. these are toxins which can be harmful to fish and often lead to fish loss. these toxins are removed from the tank by bacteria that is in the gravel bed, equipment and other essential parts of the tank. this is referred to the beneficial bacteria of the aquarium. the bacteria is created by spiking out or letting the toxin levels climb.
toxins can also be removed from the aquarium by water changes. nitrates the lesser of the three toxins can also be removed by plants in the aquarium. aquatic plants feed on the nitrates. the fastedr growing the plant, the more nitrates it requires.
once each of the three levels have spiked and then zeroed and stabilized, the tank is cycled and the bacteria is established in the tank. you may notice a slight white milky cloudiness which signals the end of the cycling. this is called a bacterial bloom. when adding fish it is best to add them slowly so as not to overwhelm the bacteria colony with the increase in waste matter.
hth
semper fi