The color can vary from green to purple to red to black. It's all pretty much the same stuff. It is a sign that there are too many excess nutrients in the aquarium. Are you running a protein skimmer? It sounds like your clean up crew is large enough and an urchin will usually keep it in check. You may need to reduce the frequency or volume of your feedings. It will also help if you can manually remove it when you do water changes. _________ Diamond Bits USA -- drill bits and bulkheads -- Check out our new lower prices! |