Dave I have used sprinkling successfully twice. Both times it involved a limited sand vein. I have also used a pipe method to place the bentonite at a specific location. In all 3 cases the leak pulled the bentonite into the problem areas and they stopped. These were not , IMO , serious leaks like one has with fractured rocks or large porous sand seams or overall bad dirt. We used drilling mud (aqua-gel) which contains bentonite.