+1 could not agree moreGranulated carbon is commonly exhausted in a few days in a reef tank... Not bad if it is good carbon. look at some of the sponsors for "good carbon" bulk reef suppy is a sponsor I believe. There is a correlation between some types of carbon and issues with HLLE and algae, but that is not the good granulated kind. I have seen some really awesome tanks that never run carbon and other really awesome tanks that swear by it...... it has its place for sure, but there are other ways around it. I like to run a little every month or so for a few days, but not near what most people do.