"Tom Shea" wrote in message
...
this idea was posted here by someone years back: let the pond leak until
it
stops (sounds like you already know where that is....) make some kind of
mark or line somewhere at the surface. add just enough water to bring
the
level back up a quarter inch or so (depends upon how fast the leak) turn
off all filters, airstones, waterfalls, etc to allow the water to be as
calm as possible. go around the edge of the pond, and very gently drip
some milk close to the edge, a little at a time, watch whether or not the
milk gets sucked towards the liner, and it will show you where the leak
is. for quick patch, you can use a swimming pool wet/dry patch... when
there is time, patch tape inside and out will do it. I also cover the
patch tape on the outside with the stronger tape made for joining two
liners.
snip

I'd submit that this technique will not work if your leak is in a water
feature. I speak from experience. My stream currently has a leak, and since
my pump is set fairly low, it will leak and leak and leak.

BV.