srw
It's a bit more complicated than that...
To tell if the dog has been drinking vinegar or eating Rennies? Even if true (I suspect not - I can't think why anyone needs to test the shoot they clean up; shoot is shoot, whoever produces it) you don't need a Chemistry GCSE to use a bit of Litmus paper.The two doing the job in the Owlcotes Centre carry PH test strips.
Oh, and it's pH.