here's what I did. I cleaned a section of the cc very well, very well, then removed 2-3 nets. I did this with each water change and did weekly water changes, it took awhile. You'll have to move lr around and such, which will stir up more crap. if you don't clean the cc before removing, all the crap in the cc will be in the water rather than in the bucket to you drain the water to.
As far a cycling, if you move a tank, distrube the baterica/filter stuff or if something dies or you add too many fish you may have a mini cycle.
Normally, if a fish dies, you're okay, if a bunch die...then you might have an anomia spike, same with adding fish, if you add more fish than your tank can handle, then the anomia may spike and cause another cycle.