Natural Swimming ponds.

More people are converting their old chlorine pools into "Natural Swimming ponds" that use a combination of water plants and other sustainable features to filter and purify the fresh water so that you have a virtual natural swimming hole in your back yard.

Natural swimming pools are naturally filtered and cleaned, providing an unparalleled swimming experience in the comfort of you own garden

You can learn more here:  

http://www.Naturalswimmingpools.com