That's a bummer. I wish I had the knowledge to help you jump start your recovery, unfortunately I'm a pretty laissez-faire reefer. Maybe look into old tank syndrome? Maybe go back to the basics adequate clean up crews, flow, water changes, possibly cleaning sections of sand bed for accumulated debris. Just throwing a few ideas out there. Fortunately there's plenty of really knowledgeable people on this site. I think Jeremy St Louis does some tank maintenance as well. Good luck Kurt