Before my Charge 5 just outright broke, I found that the accuracy of swim tracking was just getting worse and worse. I know you probably aren't looking for a new device (yet), but should your Fitbit break like so many others' have, I have to give high praise to the Garmin I'm using. Even when my Fitbit was working properly, just getting the time and distance (as inaccurate as it often was) seemed so simplistic. I now get HR monitoring underwater, interval times, lap times within those intervals, stroke detection (admittedly it occasionally detects the wrong stroke on my first laps of an interval because I glide underwater for too long), strokes per minute, etc. Best of all, all of that information is available right away as soon as you finish and save. You can also see your distance on the face as you're still swimming too.
