On Wed, 05 Sep 2007 20:32:59 +0000, Larry wrote:

Works great,
change it every 100 gallons or when the water starts tasting slightly
metallic, indicating the carbon has loaded up with benzene, which
distillers also distill out of the water.

The CRC lists 15 substances with the same boiling point as water.
A simple still won't even remove alcohol or methanol, or acetic acid.
Of the hundreds of known chemicals with boiling points near water,
few, fortunately, are likely to be found in high seas water. Some
rivers are a different story. I would't trust some river water not to
attack gelcoat or aluminum. You wouldn't have the urge to put it in a
nice clean still. Distillation is OK but it costs a lot. In my
opinion, either RO or distilled water should be run through a carbon
filter. Gets the benzene and a lot more. Carbon ought to take out
'plastic taste' but I have not put it to the test.

Casady