I swam 2 km tonight. I could have done more, but it was going on 9:30 so I thought I better get out to make sure I caught the 10:08 bus.
It took me an hour and seven minutes to swim the 2 km (that's including time I stopped to rest between some laps).
I ate dinner (20g carbs) about two hours before swimming. Did a 50% reduction in bolus. My blood sugar was 10.7 (193) before starting, 4.6 (83) after finishing, and 8.9 (160) when I got home an hour later (I showered fully and also stopped for groceries). I didn't reduce my basal rate at all. I think I'm finally getting a better hang of how to handle my blood sugar.
I may go again Sunday during the day sometime. If not, I'll definitely be going Monday night.