Bring it down slowly with small water changes. Take out some SW and replace it with RO/DI. High salinity really messes up your fish's kidneys. I would start as soon as possible. 1.028 is not super high, but I wouldn't leave it there. Fixing it all at one time is not what I would recommend. That would be to sudden of a change and will stress your fish even more then what they are already being stressed by the high salinity.