Middle down should be plenty of light. However, the color also depends on the bulbs you have and the water perameters.
It is not a "palyathoa" It is in the zonathus gigantus family and it will change colors as the wind blows as well as temp, lighting, flow....etc.. good luck!
Please elaborate why you think paly's don't change under those statements above....
"zoanthus gigantus" is not a family. It is a binomial species name which should have the genus capitalized and the whole thing italicized...Zoanthus gigantus. If it's going to be hammered into everyone who mentions the word "paly" in a post, at least let's do it correctly.