Coat with 1/4" of thoroseal. It's at home depot. OR mix masonary (S TYPE)
cement with Behr acrylic and coat at 1/4" thick. Both available at Home
Depot. Both will limit the time you have to wait for your pond to get rid of
it's calcium hydroxide. Concrete is porus to 4-5" thick. If you're over 5"
you're probably fine.

Sam

"Zeev Yelin" wrote in message
om...
Hi,
my name is Zeev and I'm not even a newbie. I'm in the process of
building my first KOI pond. any comments will be much appreciated.

right now the status is that the concrete infrastructure is ready
(pond and filter housing abutted to it ( the filter housing will house
an immersed pump that will take its water from the surface and the
bottom and will be located between two filters a "skimmer" and a
"bottom feeder")

Now I was wondering how best to seal the poond I thought of plating it
with plaster ( which materials?, any plaster mix that will not harm
fish or plants, ).
Also what's your experience in instaling light sources inside the
pond or is it preferrable to light it from the exterior.
thx
Zeev