I applied both the DB liquid and granuals to a very leaky sandy pond several years ago. In looking back, the dam was pretty sandy and to get that minimally clayey sand, had to be dug down to the rock. In a miscommunication with a contractor, he pushed it down while I was out of state, so I wasn't able to follow up report on the DB.

But, what I did notice was a certain clearing of the water following application. I do believe it attaches to the clay particles in the water and settles them, which has to be helpful. I can't verify this, but seems if water is always seeping away from the pond, some of those settled clay particles will find their way to plugging tiny passages. I wouldn't expect it to help with a singular moderate or large leak, but would help with seeping over a broader area.

Self-educated rednecks, the real intelligentsia.