Well it works , and produces skimmate ! I ran a seaclone skimmer on it before this reef octopus . Also meant for 100 gallon tank . It also worked just fine . Produced tons of skimmate . Was just getting old . Also the reef octopus has been running for four days with the valve fully open . I slightly closed it . And it's skimming .When I said heavily stocked , I meant it . From what I read on the reef octopus I purchased is , a bit over 100 gallon tank , 75 gallons in a well stocked tank . So I shouldn't have this on my tank when it works ?