1. Our two Groco K toilets are now exactly 30 years old and still work great. Why anybody would replace them is beyond me.
2. If you over-tighten the bolts holding the bowl to the pump, you can break the bowl. When this happened to us, there were no new bowls available. Fortunately, one of the yards in Turkey
, where we were cruising, had a Groco bowl lying in the junk heap!
3. Sand comes into any salt-water head and eventually wears the cylinder. There's an easy fix: Remove the pump and take it to a good machine shop. Have them grind or drill out the cylinder so it's round again. Then find some Teflon or other long-molecule self-lubricating plastic (the generic ones are cheaper than Teflon and just as good) and have the machine shop make you a piston that JUST FITS the cylinder. This piston requires no rings and works better than the new toilet did! If you're adventurous you can design the new piston so it comes up about 1/4" more than the old one did -- don't overdo this or you'll block the exit hole at the top of the stroke!
4. Tell your guests to partially empty the bowl first, then pump new water
in. This cuts the number of pump strokes by about 2.