Are you a member of TCMAS. It is the local twin cities aquarium society. There are a lot of very knowledgeable people there. I live north of Minneapolis. I really have no idea what is up with your tank but I agree lower the light slowly a couple inches a week, all at once would not be good. I don't know which store set up your tank. There are good ones and bad one. I like Saltwater Empire in Bloomington, they have always given me good advise.Wish I could find a fellow reefer here in Minneapolis that could help without wanting 60 an hour


