A skimmer is typically not needed in a reef tank if you have enough live rock , live sand and critters to do some cleaning. Quite often over skimming will cause bigger problems than not using a skimmer. I would think that with your emperor and live rock and sand you should be all set. I run a reef tank without a skimmer and I have never had problems and I even have few fish. I also have seen tanks with some of the most beautiful specimens ever in tanks that go skimmerless. This is really a debate of the ages, but whatever you do, dont overskim.
--andy