Source water is treated by mixing a first component selected from the group comprising neutralized phosphonic acid compounds, neutralized phosphonate compounds, neutralized derivatives of phosphorus, neutralized anti-scalent polymers, and mixtures thereof, a second component from the group comprising chlorite salt and chlorate salt is admixed to the mixture of the water and the first component, and water. The water and the first and second components are present in amounts sufficient to form a stable liquid composition in which there is substantially no conversion of the second component to chlorine dioxide.