Hello from Qualicum Beach, British Columbia, Vancouver Island, Canada!! \n\nDecided 2 weeks ago to fulfill a longtime dream and build myself a fish pond. 3 ft deep, 11 ft long, 5.5 ft wide. The hole will be finished today or tomorrow so it's time to start thinking about coping stones and edging!!\n\nMy friend gave me some concrete flag stones that I was planning to use as coping stones, which some pretty pink slate rock as the edging. I would like it to be (mostly) level with the existing ground. \n\nMost of what I've found online says to carve out an L shape around the edge, and put the coping stones on top of the liner. However I also came across one site that shows the coping stones under the liner. \n\nI'm concerned about chemicals leeching from the concrete flag stones into the pond. Is this an issue?