Like little said, it won't help. It kills bacteria and other microscopic life. The cycle is caused by the tank not having enough beneficial bacteria to break down the ammonia created by waste (such as the life that died off from the live rock) - when the beneficial bacteria builds enough in the rock, the cycle will more or less be over.
Every time you add a new source of life (fish, for example), you'll have a mini-cycle as the ammonia increases and the bacteria population grows to match the new intake. If you have an established tank w/enough natural filtration, this mini cycle will not be noticeable.