Gosh there are so many questions that I'd have before I could say what happened. Did you have much free stone, was it cored, was it packed in and more. Once you have a leak they are hard to fix without draining and some construction work. Bentonite will help if you find a specific leak, but it needs mixed into the soil. I don't like it as a permanent fix. It will mess up a filter if it gets into it. It's a clay, so it will stop water permeability. So will the other stuff. Did you have good clay? I have seen a lot of leaky ponds in my day and they are rarely a simple fix. How valuable is this pond to you. A poly liner will do it, but that is super expensive. Some ponds will seal themselves off over time, but usually it takes draining and adding a clay blanket packed in. Some old timers would put a bunch of carp in a pond to keep the mud stirred up and settle into the leaks, but you wouldn't want that if your using it for potable water. I had many leaks in our 30 ponds over the years and a permanent fix always involved some form of rebuilding. If you know right where the leak is you could drain it below that point and get a backhoe and dig it up and repack with clay. do this as a T trench. If it's new there is no better time than now to fix it. Good luck
For those who think using pond water is bad, it's all soft water and safe with filtration. We used pond water for 30 years and never had any issues. A floating prefilter and a sand filter with holding tank below the pond gave us crystal clear water and safe. You can even add a chlorinator.