MIC or microbiologically influenced corrosion is the result of certain types of bacteria in the water that attack steel and copper pipe. MIC can be recognized by the presence of orange or black tubercules or black mud?like slime in steel pipe and blue or green tubercules in copper pipe.
The best approach to address this situation is to submit a sample of the corrosion by?product to a laboratory for testing (such labs can be found on the internet) and identification of the microorganism responsible. Once identified, a treatment strategy can be developed. This may involve altering one or more environmental conditions inside the pipe such as: oxygen levels, pH, temperature or residual chlorine content. If the problem is MIC, treatment of the water will be necessary each time you test or flush your system. Introducing a fresh supply of water and oxygen may allow the MIC to renew its attack on the pipe.