As long as you have a good way to remove excess nutrients in the water you should be fine either way. Personally, I like running skimmers on my tanks and my zoanthids IMO look better and are healthier because of it. It also helps remove many of the excess organics that would just cause more of a burden on my secondary nutrient exporters down the road. I can think of many more pros than cons. I have seen the term "dirty water" a lot lately and think it has been used in a wreckless manner by those promoting it without really explaining what they mean. I have a problem with the term because, more times than not, it is taken literally the wrong way by newer hobbyists, and is a disaster waiting to happen. Excess nutrients break down and this leads to algae, cyano, and most importantly tank crashes and dead livestock. Normal feeding of fish will provide plenty of nutrients for them and no need to give extras for the zoanthids. Sounds like you are already doing well with what you have and I am sure zoanthids will be just a easy for your to keep. Just be sensible and provide a stable tank and keep a good nutrient balance without overloading your biological and mechanical nutrient exporters and your zoanthids will grow like crazy.
