Maybe it is the water. I'd like to see the MSDS for that "additive" they put oin. Can't be good.
Also I can't tell you why-any reasons- but when my hounds get sick/diararhea -which thank God is very rare but when they do- I often feed them raw beef muscle meet or tripe or heart. I thought maybe it was easier on their system to digest or something. At any rate it seems to help them get well fast. But I couldn't say whether it is luck or reality based!