The machine blends iron, bleach and sodium hydroxide to form a dark purple liquid mixture of ferrate, salt and water that gets metered into the water supply. (The color disappears instantly as it reacts with the water.) Common disinfectants ozone and chlorine can turn the water cloudy or, worse, leave behind harmful chemical by-products.

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In Guernsey, salt can only be used outside the water catchment area because it can contaminate the water supply, so the de-icer CMA needs to be used.

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