I've tried bentonite on 3 different ponds with leaky, sandy bottoms with no positive result. I used a LOT of it, tilled it in, etc.

I do have a friend that had the oil co that he worked for bring the used mud(bentonite) from a well and dump copious amounts on the bottom of his leaky pond. That worked but I have no idea what it would have cost in that quantity.

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