Patent ID: 7501067

Claim:
A method of treating a body of water to kill microorganisms by maintaining an effective concentration of at least two different biocides comprising: adding silver ions to the body of water to maintain a silver ion concentration effective to kill microorganisms; adding sufficient bromine to the body of water to maintain a bromine concentration effective to kill microorganisms; and adding a chelating agent selected from the group consisting of 1-bromo-3-chloro-5,5 dimethylhydantion, 1,3 dichloro-5,5 dimethylhydantion, 1,3 dibromo-55 dimethylhydantion, anthranilate, saccharinate and sulfadiazine into the body of water to maintain the effectiveness of the silver ions in killing microorganisms and the effectiveness of the bromine in killing microorganisms in the body of water wherein the level of bromine can be maintained at lower levels than if bromine were used along in killing microorganisms in the body of water.