I have read it’s beneficial for my dogs if I put a small amount of apple cider vinegar in their drinking water. I have found that by doing so, there’s a dark mould (but not mould) like growth up the sides of their water bowl. This appears within 24 hours of adding the vinegar. Does anyone know why this is happening and if the water is still OK to drink or not?
Posted by mom81879, 10th May 2016