NZ moss 'tea bags' clean US pools

Moss pulled from the bogs of Westland is cutting the whiff of chlorine from American swimming pools, using its natural properties to fight bacterial slime.

A Minnesota company, Creative Water Solutions, has patented a product it describes as like a large "tea-bag filled with New Zealand moss" to condition water in backyard pools - and hopes to upscale it to public swimming pools.

After a two-month trial, caretakers of an Olympic-sized pool in St Paul, Minnesota reported that sphagnum moss drastically reduced the need for chemicals and maintenance, while swimmers reported a drop in hot, stinging "chlorine" eyes.

With the moss controlling bacterial colonies, called biofilms, the pool needed two-thirds less chlorine than before, reported the global edition of the New York Times.

The Minnesota company said biofilms built up in spas and pools and absorbed chlorine, requiring ever-greater doses to keep the water free of bacteria. With biofilms under control much less chlorine was needed - just enough to keep free-floating bacteria at bay.

Moss harvester Lynda Sutton said her company, Sutton's Moss of Kaiata, near Greymouth, had been supplying Creative Water Solutions for about eight years.

She would not be drawn on what special sterilising properties the West Coast moss might have, saying she feared giving away trade secrets.

The sphagnum moss is bundled up and airlifted by helicopter from the rain-soaked forest districts of the South Island's West Coast, where it forms squishy carpets.

Most of it is sold to the fresh flower industry and used to wrap orchids and germinate flowers - generating millions of dollars a year for the West Coast economy.

David Knighton, the United States doctor and inventor behind Creative Water Solutions, is reported to have stumbled across its pool cleaning properties after reading it was used to pack wounds in World War I.

In Minnesota it is believed mats of sphagnum growing in the state's lakes are partly to credit for its famously clear water. The natural buffers in the moss help stabilise PH.

A Ministry for the Environment report on the conservation status of New Zealand moss noted sphagnum was mostly harvested from Department of Conservation land already damaged by logging or mining.

It grows in the United States, but New Zealand exporters have the advantage of an established industry that hand-harvests moss and airlifts it to the road to reduce environmental damage.

The City of Saint Paul website cites "amazing" results from using moss at its public pools.