Natural Swimming Pools: More Beauty, No Chemicals

Natural Swimming Pools: More Beauty, No Chemicals:

"Natural swimming pools use plants or a combination of plants and sand filters to keep the water clean and clear without chemicals. They were developed in Austria and Germany in the 1980s and have since grown in popularity worldwide. They can be designed in a multitude of ways: Some look like natural ponds; others may be disguised as standard tiled pools." 
-- Houzz.com