Very pleased
I wasn't convinced these would work but gave them a try. As we've got 3 dogs I got 3 jugs instead of using them in the bowl and run with the 3 that way there is always one ready that the rocks have been in for the 12 hours prior to drinking. I leave them in for 2 months or just over in winter and around 4/6 weeks in summer when they are drinking more. Grass is green and I'm convinced they work as everyone else says don't know how but they do.