Originally Posted by thominil
Letting it sit in saltwater for 24 hours is calibrating it. I wouldn't worry about the reading until the 24 hours is up. Even then the readings may be off as hydrometers aren't the most accurate, but they work.
That's not calibrating... that's just "breaking it in" or whatever they call it. Calibration implies that you can change the reading to match a known salinity. That's one of the problems with swing-arm hydrometers - they read whatever they read and you can't change it. 1.028 is a little high, but with a swing-arm hydrometer you could be +/- .005 easily. So getting it lower is probably a good thing.
You might want to add a refractometer to your Christmas list. One of the cheapest and best investments you can make starting out.