I gotta agree with Ponds and Kayak. I doubt the wisdom of using bentonite. It is nothing more than powdered clay that expands when it gets wet. The best application is tilling into the ground to lessen the permeability. You are betting that it will find the leak and stop it. It is my understanding that most liner leaks are caused my animals stepping on and breaching it. It is also my understanding that liner failure is rare. Your breach is probably not deep and is probably not very large.

I don't think you have many viable alternatives other than letting it leak down until the leak can be identified.

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