Bitumin is the perfect sealer.
--
Kind Regards
Cameron

"SkyCatcher" wrote in message
...
Hi,

A friend has built a pond lined with concrete/render to which he added a
waterproofing sealer additive. He wants to add a "top" coat sealer to
ensure
it holds its water and asked my advice!!!

He is not going to keep fish - just wants it for plants and whatever
wildlife decides to move in. I onlu know of G4 in the UK for sealing ponds
with fish but that is very expensive. Can anyone suggest a sealer to use?

Ta,

Sky