In article ,
says...
Mark Borgerson wrote in
g:

RO filters DO NOT pass dissolved metals. If they did they would be of
little use in generating fresh water from sea water.

Unless you use a laboratory-quality still, RO water will be as pure
as distilled water if the filter is operated properly.


Mark Borgerson



Then were does the 100ppm dissolved solids come from?

RO will NEVER be as pure as distilled water....

Not at the laboratory still level, for sure. But it compares
well to large-scale distillation plants used to produce
drinking water:

http://www.oas.org/dsd/publications/...ea59e/ch21.htm

"Desalination of seawater is a relatively expensive method of obtaining
freshwater. The MSF system has proved to be a very efficient system,
when properly maintained. It produces high quality product water
(between 2 and 150 mg/1 of total dissolved solids at the plant in
Curaçao); TDS contents of less than 10 mg/1 have been reported from the
VC plant in Chile. Because the water is boiled, the risk of bacterial or
pathogenic virus contamination of the product water is minimal. "


Shipboard evaporators also have other problems: the resulting water
needs pH adjustment and and treatment to kill bacteria, since the
water is often distilled at only 60 deg. C.

http://www.facetinternational.net/potabilizer.htm

Mark Borgerson