I think from what I have read on the subject that if it's a healthy stool, colour width so on and it floats it a good thing. It's not a good think if it floats due to there being undigested fat/oil in the stool,this would make it float. If the stools are narrow this would suggest inflamation in the bowel and if they are light in colour that may mean that there is not enough bile getting to the bowel from the liver.