"Drakanthus" wrote in message
2) Drain, then fit a pond liner into the nice neat hole
2) sounds better but I am worried about placing liner in a cement-lined
hole. I once saw rain get between liner and the wall of the pond.

The best solution would be to fix the leak, but how you go about finding
the
leak I haven't got a clue.

That's the easy bit, just let the pond drain and it will stop when it gets
just below the leak.
But what do you do with those 3ft+/- long Koi meanwhile?

Personally I'd go down the Butyl Liner route as if the concrete pond is
leaking in one spot it will soon leak in others. I've had a pond (with Koi)
made that way for over 20 years and no problems with liners coming away from
the cement skin underneath. You would only experience such a problem in very
heavy, pottery like, clay that would not allow any water to drain.

--
Bob

www.pooleygreengrowers.org.uk/ about an Allotment site in
Runnymede fighting for it's existence.