Question: I have been noticing a distinctive odor emanating from my main display tank that has a mild quality to it that I can only think might be from coming the corals in my display. :~ I'm noticing that the smell is similar to that of Acroporas when they are out of water. And, after I do a major water change, the smell is gone for one or two days and then it's back again. If this odor is being given off by the corals, is there a way to rid the smell, such as increasing water circulation or something else I can do? Note: My skimmer is working properly and even when the collector is empty, the odor can be detected. Just thought I would rule that possibility out. Thank you for your comments and suggestions.