Amanda. I like starting my brug cuttings in water, too. But I don't change the water at all. Brugs actually secrete a rooting hormone that helps them to make roots in the water. If kept pretty warm, the cuttings usually start forming roots within a week. The water never gets funky.
As soon as you have white 'nubbins' showing up on the stems you can re-pot them. Or you can wait until the roots are lengthening out a bit, but don't wait too long because roots formed in water are not as strong as roots formed in soil. You should see roots starting within a week. Then the cuttings stand a much better chance of taking off once you pot them up.