Your marina manager is wrong...
That would be tantamount to saying "all engines smoke." But engines shouldn't smoke and toilets should NOT leak. If even the new heads he installs leak, it's because he doesn't know how to install 'em correctly--he overtightens discharge fittings or puts too much sideways stress on the discharge hose instead of replacing the straight discharge fitting with an elbow...single hose clamps instead of double, etc. His sort of "advice" irritates me because it only encourages owner neglect of problems that are actually very easy to solve. If kept properly lubricated, a PH II (PHE II is the electric version) should require rebuilding only about every 4-5 years, and can easily last for 20 years or longer. If lubrication is neglected, the rubber o-rings and seals wear out much faster. Over time, it can also wear the inside of the pump cylinder...salt and grit can score the inside of the pump cylinder--eventually to the point where rebuilding no longer can help. But even the most meticulously lubricated toilets require rebuilding at least once every 5 years to keep 'em working at peak efficiency. Ever wondered why a new toilet doesn't need any lubrication for at least a year? That's because they all leave the factory slathered with thick teflon grease that lasts at least a year, sometimes two, depending upon how much use the boat gets. When it does need lubrication, you can either fight the never-ending battle of pouring something down the head that just washes out in just a few flushes...or you can spend about 10 minutes just once a year (and about $5 once every 2-3 years instead of buying bottle after bottle of whatever you've been pouring down the toilet) to replace the factory lubrication as part of preventive maintenance: Buy a tube of SuperLube or other Teflon grease (ONLY teflon grease...don't use anything else). To lubricate a manual Jabso toilet, remove the two screws that hold the top of the pump on...remove the top, lift the pump handle and put a healthy squirt of teflon grease into the pump cylinder...pump a few times to spread it all over the inside of the cylinder and the rubber parts...put the top back on...you're done till next year.To lubricate a PH II, remove the air valve (flat square little nut with a hole in it on the front of the pump that can fool you into thinking it's molded into the pump body)...put a healthy squirt of teflon grease into the pump...pump a few times...clean the air valve and put it back...and you're done till next year. The best time to do it is the fall as part of winterizing--after you've run antifreeze through the toilet. The grease protects the rubber parts in the toilet from drying out over the winter and extends their life. This and a whole bunch of other useful stuff is included in my book.