I disagree, if you throw away you old filter (as suggested by the manufacturer, which has you replacing them far too often :?), from an established tank, the tank will be fine with a brand new filter. There are tons of bacteria in the water, on the substrate, decor and fish themselves that a cycle will not restart. However, if you are thinking ahead, you can seed your new filter from the old filter. Bacteria will not migrate from an old filter to a fresh filter. The "offspring" of the bacteria on the old filter will colonize the new filter.