Hi Jim, We have three German Shepherds and an a/g pool. One of the dogs habitually stands on his hind legs when trying to catch a Frisbee. No damaga to the liner so far. We keep their nails trimmed and we taught them where the exit is. Dogs tend to get out of a body of water at the same place they went in, and since Pax almost always dives in off the edge he had to be shown how to get out at the steps. It took two lessons for him to learn how to exit. Occasionally, a dog will push off the side after he's retrieved his toy. We have no tears or scratches in the liner. IS there more fun than swimming with dogs????