Peggie,
The dilemma is the Lloyds certification for thru hull fittings, which call
for fire proof valves against your years of experience. My solution will be
plastic valves at the plastic holding tanks in deference to your experience
and 316L valves at the hull. This solution should satisfy both. Thanks for
the Muriatic tip. It should have been obvious, but I did not consider scale
build up as an issue.
Steve

"Peggie Hall" wrote in message
...
Steve Lusardi wrote:
Peggie,
Won't the hydrochloric acid eat the porcelain bowl?

Nope. Won't eat rubber either. In fact, owners and pros have used it for
decades to clean sea water minerals out of raw water intake hoses and raw
water engine cooling systems. The instructions for cleaning/descaling) the
Lectra/San electrode pack also call for a 12% solution of muriatic
(hydochloric) acid, flushed into the unit through the toilet.

PS Just received all the stainless pipe fittings and flanges for the
plumbing yesterday from Texas yesterday.

SS fittings in the sanitation system plumbing??? Not a good choice, 'cuz
urine will corrode 'em. At least one trawler mfr who puts all fittings on
the top of the tank, with a pickup tube inside the tank on the discharge
(a great idea) used stainless fittings and pickup tubes--a VERY bad idea,
'cuz the tubes are corroding, even falling off in pieces inside the tank,
in just a few years.

--
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://shop.sailboatowners.com/boat_odors/