Caribsea NO-NO3 (No-Nitrate) 1 gallon. Nitrate troubles? Current research shows that sulfur based denitrators hold promise for significant nitrate reduction in heavily bio-loaded systems. These experimental biologically driven de-nitrator/reactors rely on a combination of pure sulfur, aragonite and sulfur reducing bacteria. NO-NO3 is that media. Go ahead and experiment. CaribSea has you covered.