I recently had several fish die do to lack of skimmer and poor water quality. It was a few days before I noticed, but my two Anemones had died also. Once I pulled them out I started noticing a strange mold growing on both the rocks along with the sand around the rocks that the Anemones were attached to. Any one have any idea on what that is? Can I just clean out the bad area and do a water change or should I start over with all new sand?