Try to keep the concrete damp for at least a week, better a month, then
allow it to dry for a few days. The moisture helps the concrete to cure,
which makes it stronger and more watertight. The watertightness limits the
migration of the calcium hydroxide solution, which is a byproduct of the
hydration reaction. Once the concrete is allowed to dry, then the calcium
hydroxide near the surface will react with carbon dioxide in the atmosphere
to make a calcium carbonate layer the is on and slightly into the surface of
the concrete. This makes the concrete even more watertight, limiting the
flow of the very high pH calcium hydroxide into the pond water.
--
RichToyBox
http://www.geocities.com/richtoybox/pondintro.html


"Gunnar" wrote in message
news:5C1Qa.3405$zd4.1087@lakeread02...
just made new waterfall made it with portland cement should this be coated
with anything before running. or sealed with a sealer of some kind?