The secret, says David Antcliffe of Ponds In the City in Toronto (pondsinthecity.com), is to create a natural ecosystem that mimics as closely as possible the processes found in nature, which is surprisingly simple if you follow a few sound principles. Instead of a pool chlorinator motor, the pond features a base of rocks and a filter system that together create the perfect conditions for the invisible, odourless beneficial bacteria that are the real sanitizers.
Because an artificial pond is a closed system, filters are needed to keep the water moving and oxygenated, but other than that, the process emulates the self-cleaning system of a natural pond. The filters, generally a waterfall-type main filter and a second, submerged type that filters the deeper water of the swimming pond, remove large debris and contaminants and oxygenate the water. A smaller basket filter continually skims the surface to remove small items that collect there, such as leaves, and can be cleaned out by hand every few days or so. In addition, because there are no artificial sterilizers such as chlorine, beneficial bacteria can grow and thrive by attaching themselves to rocks and other underwater surfaces. By consuming organic waste and contaminants the bacteria, in effect, "polish" the water, keeping it crystal clear and perfectly balanced.
Installing a pond is the same whether you're putting in a small ornamental version or a larger one suitable for swimming, says David. First, the hole is dug according to your design; his designs all feature a one foot-deep ledge all around the pool, for shore plantings. After the installation of a special high-resistance rubber liner, the pond floor is filled in with carefully placed and sized granite rocks; in place of regular river rocks, he says, you might opt for flagstone to make standing and walking on the bottom easier, or create a pea gravel "beach" at one side. Finally, the rest of the pond is planted, with a combination of deep-rooted and floating aquatic species. The pond's soil-free design makes the root systems very sturdy, says David, as well as making the water clearer and more pleasant for swimming.
A fully planted 20' by 25' pond large enough for swimming can be yours starting at around $25,000, depending on depth. Not bad for a little backyard slice of nature.
Images courtesy of Ponds in the City.
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