Thanks for the encouragement.
I have put some dry bentonite in a couple cracks several feet from the pond to act as a bit of a dam if the sludge flows through the crack and gets that far, but for the most part I think I have a better chance of getting the bentonite deep into the porous areas, if I use water to carry it there.
At first I was going to try to put it into the cracks dry, but it seemed like the bentonite would probably get jammed up before penetrating deeply into the tiniest cracks deep in the dam. I noticed it seemed to do this with the bigger cracks I tried to dam up with it.
So what I am trying to do is use the water to carry the bentonite into all the tiny gaps where water might get through. For the first pour I mixed it quite thin, more like cream of mushroom soup. I did my best to pour as much in as the crack would suck up. From watching my garden I am pretty sure the surrounding ground is dry enough to suck away most of the water over a course of a week. The cracks are sucking up a lot on the second round but noticeably less than the first, so I think it must be working.
If it's a big crack, after the first pour, I am then mixing it just a touch thicker on the second week. I am also making a point to start with the cracks closest to the pond, moving outward. The compaction I have done on the inner exposed banks of the dam where the water has gone down prevents the sludge from flowing into the pond.
I am also making sure to water the banks of the actual exposed pond basin twice a day to prevent them from getting too dry and cracking.
I've already gotten 3/4 of a bag of bentonite deep into my small dam doing this, and like Otto says, I figure that can't do anything but good.
