I rebuilt my jabsco macerator last year and replaced the corroded brass bolts with ss bolts. also replaced all other parts using service kit (including gaskets) within a year, the macerator started leaking at the gasket seal. after disassembly and inspection, the only thing that appears to be wrong are premature wear of gaskets... while living vicariously and watching YouTubers rebuild their macerators... one guy was also installing a shutoff valve between the macerator input and the holding tank output. his thinking was that pressure from a pumpout station was sucking through the holding tank output through the macerator input then output and eventually to a closed through hull. he speculated that the pressure from the pump out vacuum had blown his macerator gaskets. since this rebuild is an undesirable chore and I'm starting the second one in just 1 year... it leaves me wondering if I should install a shut off valve between the tank and the macerator to protect it from damage / gasket blow out.... I would have thought that my unblocked vent would protect my systems from the pressure... thoughts? if you do recommend a shit of valve for the above reason... whatnpsindiesnit need to be rated for to survive the suction from a pump out vacuum?