I have seen a few ponds for just swimming and though I haven't talked to the owners this is what I have observed. The sides of the ponds are steep and lined with rabble rock to keep any vegetation from growing. Also the ponds are heavily dyed to keep the sunlight from penetrating the water to suppress weed growth. Weather anything else is used in the ponds I don't know. A friend has a one-acre pond with a spring diving board and he uses for swimming. He has fish in it and uses copper sulfate to keep down the FA. I don't know what else he uses for weed control but he has only low growing plants in his pond and does use some dye but doesn't have the steep banks and rabble rocks.
