Rock Boring Sea Urchin

[bgmac]

I have a couple of Hawaiian rock boring sea urchins I picked up from a reef near my house about a year ago. They have done a great job as part of the clean up crew. I have had a few of my LRs knocked over from time to time but the urchins pay rent by keeping the rocks and glass clean. I run a cheap rubbermaid sump with cheato that lately is getting out competed by green hair algae. At first I didn't mind the hair algae because it never shows up in the display tank and I figure it must be using up nitrates and other nasties in the water. The problem lately is that I have to clean it off the cheato during water changes and I know it is reducing the growth rate of the cheato. So I was thinking I could put the urchins in the rubbermaid sump to help reduce the hair algae. The cheato should be safe because I keep it in a suspended chamber centered well above the bottom and near the surface to maximize light. My concern is the rock boring urchin in a rubbermaid container. They are pros at drilling into rock and I don't want them to find there way into a corner and start scrapping through the plastic walls. Just wondering if anyone out there has tried one of these urchins in a plastic container.