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

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.


RO sounds great and I know you love yours....but, alas, there's a long
trail of problems related to RO its supporters, and especially
manufacturers and dealers, don't like to talk about.

I don't have a boat large enough to need an RO filter---in fact
I don't have a boat at all since I donated my Windrose 18 to the
sea scouts.

I've used RO filters to generate ultra-pure water for the testing
of optical oceanographic instruments. However, we were more concerned
with particulates than with a few ppm of dissolved salts. (Scattering
makes PPB of solid particles detectable, but dissolved minerals don't
really show up). I also maintain a GE home RO system that generates
about 18l per day that is in my wife's greenhouse. It runs off the
pressure from our well. A few ppm of salts and bacterial residue
aren't much of a problem there.

Too many people forget about the bacteria piled up against the membrane at
high pressure. When that bacteria breaks under pressure, its toxins DO
pass through the membrane making your RO love boat cruise much more
interesting, but lots less fun, than you'd planned.

We had to clean our RO filters with a pretty strong peroxide solution
a few times per month to flush the junk off the filters. I suspect
that filters for seawater may need cleaning even more often, as the
lab was starting with tap water passed through a 1-micron filter.

Why do you assume that the materials passing through the filter
are toxins? Perhaps they're nutritional carbohydrates? Such
assumptions and wording seem to show a bias against RO filters
in your response. In any case, you probably get a good dose of
the same 'toxins' in your city drinking water after the chlorination
has killed the bacteria.

If you put "reverse osmosis toxins" into Google, the first 9 pages of
findings are all ads for RO systems, or "reports", disguised RO ads from
someone hawking RO products. Like reading a boat magazine, there's never a
discouraging word. If there are bad reports not from the industry, they
have them well buried in bull**** Google finds.

It's very hard to get unspoiled information from neutral sources.....

You need to be a bit smarter in your searches,then. I Googled

"RO filter bacterial accumulation"

and found this in the first link:

http://www.sciencedirect.com/science...B6TFX-42KDG2J-
N&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&view =c&_acct=C000050221
&_version=1&_urlVersion=0&_userid=10&md5
=b78fb8fa60f8aef434d57d032c5d96df

"No doubt that biofouling is one of the most serious problems associated
with the RO membrane systems which has not yet been effectively solved."



OTOH, if you get your ship's water from flash distillation, you have
to worry about contamination from volatile organics. For this reason,
many ships don't start producing water until they get 12 miles offshore.

http://www.docstoc.com/docs/2372744/...oard-Drinking-
Water-Chemical-Contaminants


Mark Borgerson