Mario, I agree with Bob. Cecil Baird is the only guy I know of who ever made this work. However, he found his leak and poured the bentonite down a pipe that he placed directly over the leak. That might mean using a diver to identify the leak source(s). If you do this, it would probably be advantageous to use pellet sized bentonite instead of the dust stuff used in the oilfield drilling. Or dust followed by pellets.

It's not about the fish. It's about the pond. Take care of the pond and the fish will be fine. PB subscriber since before it was in color.

Without a sense of urgency, Nothing ever gets done.

Boy, if I say "sic em", you'd better look for something to bite. Sam Shelley Rancher and Farmer Muleshoe Texas 1892-1985 RIP Grandpa