I have always had a bad hair algae problem. This picture shows some hermit crabs playing in it, but this was how literally most of my rock work and glass looked like. Then with an order of different types of algae eaters, I grabbed some mexican turbo snails. All the powerheads were covered worse with algae, these guys are working one of the last few places with major algae. The difference between the outside and the inside of this overflow box shows how much these things have eaten. Last is my pvc return. It was completely covered with green and red cyano types of algae. Now it looks almost like new. I've tried emerald crabs, hermit crabs, tangs, and other kinds of snails, but nothing really did a decent job until I got these big guys. If anyone needs any algae eaten, I'm going to get rid of some of them because they are doing such a great job. I have some rock in my sump they could eat for some time.