there were two pools, each quite large with a smallish land area, the whole surrounded by glass panels to prevent people throwing items in.
One of the turtles can be seen near the fence, just by the land area. (The fence has an opening by the way, so the turtle has access to the whole pool. I imagine the fence is there for when they are putting the male and female together, so they can separate them if needed). These were by far the largest exhibits in the zoo.
October 2013