[fidojoe]

Congrats on the new skimmer!

Wet dry filters basically break ammonia down into nitrites and then nitrites down to nitrates, but they can't break the nitrates down because they have too much oxygen flowing through. In order for nitrates to be broken down there needs to be anaerobic bacteria present and that is non-existant where there is that much oxygen. Nitrates are very harmful to a reef if you have too high of levels.

UV sterilizers are good for killing off everything that passes through them, both good and bad algaes, and whatever microorganisms have the misfortune to go through. It is more of a matter of preference really.

As for a cycle, what you can do is cure the new LR in a bucket or another tank before you swap the tanks out. The sand shouldn't need to be cycled being that live sand is not going to give you much if any die off, and dead sand is just that, dead.