This months coral magazine has an article in the reefkeeping 101 section talking about turnover rates in the filter tank (sump.) This article suggests that 1x turnover is plenty for our reef tanks.... That right. they are saying that only 210 gallons per hour is needed as actual return for my 210 gallon reef!!! I know the common suggestion is either 10x or match the skimmer.... I have often thought that high water flow through the sump could actually be less effective but have always stuck to the common advice. Currently I'm running about 9 times the coral magazine recommended amount at about 1900 gph!! Anyone have any comments on this?