Derek Broughton wrote:
Lar wrote:

In article .com,
says...
I have a bunch of flat rocks that I have fashioned into a sort of
fountain that allows the pump/filter discharge to spill over the rocks
and into the pond. They are mostly flat rocks and for now the water
runs over them and back into the pond very well. I am afraid, however,
that an animal may disturb the rocks and alter the flow so that the
water does not return to the pond. I would like to secure and seal the
rocks so that they are less likely to be moved or disturbed. Is there
:a
mix, like cement, that can be safely used to seal these rocks? This
pond has goldfish in it so I can't do anything that would harm them.


Wonder if the Non-toxic silocon used for aquariums will secure the rocks
well enough

My experience with silicone and rocks is that it won't work. I've never yet
found a silicone (even stuff that is intended for aquariums) that doesn't
say "not for use below water level" or words to that effect. It works for
holding sheets of glass together because the actual join is dry.

Urethane foam ("Stuff") will probably do the job, if the rocks are stable in
the first place - but don't turn the water on until it's had plenty of time
to cure.
--
derek

According to the Dow website,
http://greatstuff.dow.com/greatstuff/cons/inter_use.htm , concerning
this product, they say the following:
----------------------
Gardening
GREAT STUFF can be used in gardening to bond outdoor materials such as
wood and concrete. Make sure that the surface is dry before applying
foam. The foam will deteriorate when exposed to sunlight so any exposed
foam must be painted. Foam can also be hidden with rocks or pebbles.
Cured foam is non-toxic and will not harm fish.
---------------------
In fact, on the "Stuff" site they have a couple of pictures showing it
being used on a pond fountain to hold the rocks together ! ! ! Really !
! !

Thanks again,

Morgan