DrTim’s Aquatics FRESHWATER One & Only 64ozEliminates new tank syndromeInstantly creates a biofilterRemoves toxic ammonia and nitrite, naturallyNo sulfur or other offensive odorsNo wait needed100% naturalGood for 6 months at room temperature, 1 year at 50F. Best to keep refrigerated for longest shelf life.One & Only Live Nitrifying Bacteria prevents new tank syndrome by instantly working to establish a biofilter in newly set-up aquaria. Use One & Only to control ammonia and nitrite levels.