Brian W. Thompson wrote:
Peggy:
I remember some time back you mentioned here about the build up of "Urea
Crystals" (?) in the sanitation hose. Well I just replaced a hose that after
almost 20 years was totally blocked. The question is should something be
flushed through the system periodically to prevent this buildup - if so what
is it?

Jeff's mystical powers of prediction were about 99% on target.

A quart or two of clean fresh water, followed by a cupful--maybe two,
but no more--of undiluted WHITE vineger in the dry mode once a week when
the boat will sit at least overnight will prevent mineral buildup in the
head discharge hose--and help to reduce hose odor permeation. However,
there's no reason to flush only partway then wait to flush it the rest
of the way through...if the head discharge hose runs downhill, it won't
stay in the hose anyway...if there's a vented loop in the line, it won't
do any good for the hose on the other side of the loop if it's not
flushed over the top...from where it'll run downhill the rest of the way
anyway. So flush it all the way the way through ...enough will cling to
the hose to dissolve minerals before they can build up.

Do NOT leave vinegar standing in the bowl! It won't hurt the joker
valve or any other rubber parts in the toilet just passing through, but
when rubber is left to soak in vinegar, it absorbs it--which will cause
the seals, o-rings and joker valve to swell up and distort. Vinegar is
also safe to use in a Lectra/San...in fact, will help to increase the
time between electrode cleanings.

It's not just urine crystals that build up, btw...it's sea water calcium
carbonates. Urine crystal buildup is such a minor part of it that boats
in fresh water and toilets designed to use pressurized flush water
rarely if ever have a buildup problem.

--
Peggie
----------
Peggie Hall
Specializing in marine sanitation since 1987
Author "Get Rid of Boat Odors - A Guide To Marine Sanitation Systems and
Other Sources of Aggravation and Odor"
http://69.20.93.241/store/customer/p...40&cat=&page=1