Thanks delisha x2, as I saw your link on the (new) OT thread as well.
Ashdoes: they drink water... Mine love added acv to their water... Besides the bacteria - good bacteria - that grows as it ferments, I don't see how "all that liquid" would cause any problems. With any diet change in dogs, I'm almost expecting an initial phase of diarrhea but I could be wrong, especially since my dogs already get those probios by helping the chickens eat their feed! LOL
I've been doing ACV in the water for months now, so I'm not really worried about that. I am open to most anything, after others have tried it. I'm pretty sure a case of diarrhea anywhere in the house would not end well. Crying and cleaning up dog poo doesn't sound like fun.