The present invention provides a method of treating boiler and condensate water by the addition of an effective amount of a hydroxyamine-acid ester treatment reagent or an all-in-one treatment composition comprising a hydroxyamine-acid ester. Modification of a hydroxyamine to a hydroxyamine-acid ester generally reduces the odors of the amine while providing a means to formulate the composition into a solid form. The ester typically decomposes at conditions in the boiler to release the hydroxyamine to treat the boiler water. Other components used to treat boiler water and condensate related problems may be formulated with the hydroxyamine-acid ester to form the all-in-one treatment composition.