I have talked with tj about the possibility of using soilfloc and it seems to be a possibility in the future. While most of my pond is composed of a flakey shale - clay mix, I did bottom out in a solid shale strata. I think that's is where the pond is leaking. I did put some clay on top of this rock layer but I don't think it has been effective, that's why I
was looking into the Bentonite.