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Anne,The reason it is advised to adjust total alkalinity and pH before adding dichlor is that if the pH is not in the right range, the chlorine is not effective. Also, if the pH is too low, which can happen when dichlor is added to your raw water, the result can be accelerated corrosion of your water heater, pump shafts and seals. So there is a reason for doing it as the Northman and others have recommended. Bill