copper sulfate or coppersafe overnight 12 hours at 2X concentration should do it.

http://pmep.cce.cornell.edu/profiles...phos/copper-su
lfate-ext.html
http://www.nps.ars.usda.gov/publicat..._NO_115=116205
of course dont use copper sulfate in a "swath" in your tank, but here is
the idea.
" Technical Abstract: Aquatic snails transfer trematodes from birds to
fish and by reducing the number of snails the potential for diseases caused
by the trematodes is lessened. This article discusses a shoreline pond
treatment designed to kill aquatic snails that occur in the waters at the
pond edges while not harming fish in the pond. Two treatments at three
different rates were tested for efficacy against the rams horn snail. The
best treatment appears to be a copper sulfate solution applied in a 6-foot
swath in the waters along the shoreline of a pond. Ten pounds of copper
sulfate in solution were put out over 250 feet of shoreline. Survival of
snails in the treatment was 0% while in the controls 69% of the snails
survived. The treatment appears very promising."
Ingrid


"Robert Burns" wrote:

Thanks,
So how's copper sulfate work as a dip? I'm going ot re-pot and divide
plants this weekend. If I dip each plant before it goes back into the pond
will I get 'em? I'm putting the fish in a separate tank for a week or so
while I scrub out the pond. It's getting a bit larger too. I'll check the
hardness. What concentration should I use as a dip if it will work.