Pottsy,
I did get the granular after all. I tested some in the pond and sinks right away. My pond is mostly clay and I think my seep is very small so it may work. You should go to the sites that Davidson recommends. Good information, and something I didn't know is it may work but not right away. It can take a while to seal.

If pigs could fly bacon would be harder to come by and there would be a lot of damaged trees.