I had a little gap in my diary in which I could fit a 20 minute swim (plus changing) and thought it would be an opportunity to do some medium intensity lengths. I'd not got the pull buoy so it would be hard work.
I swam a total of 800m as 400m, 200m and 200m sets and it went very well. The 400m was done in just over 10 minutes and excitingly even after that, I managed 200m in 4:51 minutes which is a PB for that sort of set. The final 200m was only just over 5 minutes too.