Vinegar is a waste of time, and replacing joker valves is a waste of time and
money. Don Casey recommends clearing calcium deposits from the whole system using muradic acid, which is really hydrochloric acid. You can buy it dirt
cheap by the gallon or two-gallon box at Lowes, it's used for
cleaning concrete and also for adjusting the Ph of swimming pools. Should only cost a few bucks a gallon, unless you get it at a pool and spa place, where you may pay triple!
It's very aggressive stuff, but won't hurt the joker valve,
head or pipes. I've used it for several years, and it works wonders. I used to have the same frustration with the joker valve all the time, even replaced a deposit-clogged hose once. Now I just laugh at that! Such an easy fix!
Wear gloves and eye protection, and open a window. Empty the bowl, and pour the acid in till it covers up any discoloration in the bowl. If the build-up is bad, you may hear it start to bubble. Close the lid, and come back 10 min later. If it was bad, you will probably see half a bowl full of foam!
Don't worry about the foam, just give the
head one
pump or a tiny burst if an
electric head, just enough to move the acid along a little ways in the pipes. You will hear it bubbling in the pipes. When the bubbling stops after a few minutes, give another little
pump, and wait for that to stop bubbling. Put some
water in the bowl to push the slug of acid along. For an electric head, just let water come into the bowl as usual. Keep moving the slug of acid along in the pipes until you can't hear bubbling in the pipes anymore. You may then hear it in the tank - might as well go have lunch and let it eat the calcium out of there, too.
Flush well with water. No problem letting it go over the side, it is just
hydrogen and chlorine, plenty of both in the sea already. Or it can go in the
holding tank and get diluted, then get removed at your next pump-out.
Your head will look and
work like you just installed it! The joker valve and all the other
parts of your head will be clean as a whistle, and
work like a charm! You really won't believe it!
Once you have it clean, just do this whenever the bowl gets a little crusty or it stops
flushing well. If you'd rather use something a little less potent for periodic
cleaning, you can use the grocery store product CLR in the same way (but muradic acid is way cheaper).