My opions:
1. Might work if you can find the leak.
2. Might work but would take a bunch of well.
3. approx. 50 cents per sq. ft.
4. This is like filling a swimming pool. Expensive to build and expensive to fill.
5. Really, really expensive; I have been told.
Tossing bentonite won't silt the pond. It is a mineral that is mined and then crushed or pelletized.
I think I would try to find the leak and take option # 1. Of course, if he didn't core it, it may be leaking all the way along where it was tied in.
