Although it was not an original benefit, enough people have now cycled there tanks using only a scrubber that it is now the recommended way. This means no skimmer, and no waterchanges. What generally happens is that you don't get a "cycle" at all, and you can add livestock in just a few days, after double and triple checking to make sure there is zero ammonia and nitrite.

Cycling your tank has the purpose of letting the dead stuff "get out" of the rock. This stuff died because the rock was out of the water for too long during shipping, and is now forming ammonia. Well, the favorite food of algae is ammonia, and next comes nitrite, and then nitrate. So since the ammonia will be kept low during cycling, more of the natural inhabitants in the rock will survive because they are not being poisoned. Also, this extra time that the scrubber gets to develop during the cycling will allow the screen to be more ready for when you start stocking. You can then start feeding your tank heavier, sooner, since the algae will already be available to absorb a lot of ammonia, nitrite, nitrate and phosphate. Growth on the screen, however, will be limited until you start feeding, because there is just not that much to filter during cycling, since a lot of the ammonia etc that develops during cycling is actually from animals that die during the cycling itself (because of high ammonia) and not from the shipping. So after you stock and start feeding, the screen will have much more growth. Usually takes just a few days to get all zero readings.

And you don't need to add anything to get a cycle going, either. Matter of fact, you don't want a cycle at all. A real "cycle" (meaning high ammonia readings) kills the things that were living in the "live" rock. The best situation would be to get a rock from the ocean and put it in your tank in 5 minutes. Everything would still be alive, and there would be no cycle at all. But the shipping process kills a lot, and when the dead stuff gets in your water, you get your cycle. So you certainly don't want to make more ammonia by adding anything to make it worse. Just let the scrubber eat the resulting ammonia, so that the water does not get any worse. A skimmer, amazingly, actually does more harm than good, because not only does it not remove any ammonia (which is what is killing the few things still living), it removes the living critters as they get out of the rock and start swimming around, before they can get back into the rock to hide.