Zoa's can take a while to get acclimated to your tank. Sometimes up to a month or more. Some of mine took about a month in a half. Unfortunately new tanks tend to have algae outbreaks while the tank goes through the process of establishing its' beneficial bacteria population. Also keep in mind, when you have a high nutrient enviroment and lots of light that tends to encourage algae growth. Are you testing your tank water? Do you do water changes? What is the source of your water? Everything effects the tank in some way.