IME......heavey skimming or wet skimming, is probably not the best for a zoa dominated tank. zoas tend to do better in dirtier water. the most successful zoa tanks i've seen were done by people who did little to no skimming at all.
I disagree with zoas liking dirty water. I think zoas will thrive in most tank conditions as long as the tank is stable. Stability is key. I've had alot of success using a skimmer on my tank. I honestly don't think I would ever run a tank without a skimmer.