Portland cement and sand will work fine. Brick mortar has lime added to
make it more buttery. The cement will have a high lime content, creating a
mixture with a pH of about 13, but once it is set, it will not cause a
problem, due to carbonation where the lime reacts with CO2 from the
atmosphere. Some of the mortar could fall into the pond without causing a
problem due to dilution, but if you drop very much in, it will raise the pH
to the dangerous level. Keep an eye on the pH and if it stays below 9.0,
don't worry about it. If it gets higher, do a partial water change to get
it back down.
--
RichToyBox
http://www.geocities.com/richtoybox/pondintro.html


"IanQ" wrote in message
le.rogers.com...
Man oh man oh man do I wish spring would arrive so I could start
defrosting
my poor little pond!

Time to start planning what to do once old heathen winter gets the heck
out
of my back yard. One task is to cement the flagstone around the pond
perimeter, now that we've had the pond for a year.

So, question is, is there a specific type of cement I should use? The
flagstone is around the external perimeter of the pond, but there is a
chance some of the water(especially rain water), would come in contact,
and
being a bit sloppy, a chance or 2 I drop a shovel of the stuff into the
pond! grin

Guess I want to be sure I don't buy the wrong cement next time I visit
Home
Depot.

Thx in advance...


http://public.fotki.com/BrampTTon/the_home-1/the_pond/