23 s/m.

24 s/m.
Anniversary challenge 3/3.
(rest day after this; I super ded)

23 s/m.
Anniversary challenge 2/3.

22 s/m throughout.
Anniversary challenge 1/3.

24 s/m throughout.
(rest day after this; preparing for anniversary challenge)

24 s/m.
More stroke rate experiments:
24 s/m 4:59.8
28 s/m 4:41.8
22 s/m 4:56.0
26 s/m 4:49.6
20 s/m 4:54.5

24 s/m.
Tried different stroke rates:
28 s/m 4:51.3
26 s/m 4:55.9
24 s/m 4:58.4
22 s/m 5:03.3
20 s/m 4:58.7

20 s/m.
Thank you Halloween challenge.

19 s/m.
Halloween challenge day 6 - complete.
(rest day after this; I ded)

19 s/m.
Halloween challenge day 5 - 89.44% done.

19 s/m.
Halloween challenge day 4 - 71.45% done.

19 s/m.
Halloween challenge day 3 - 53.52% done.

19 s/m.
Halloween challenge day 2 - 35.57% done.

19 s/m.
Halloween challenge day 1 - 17.70% done.

19 s/m.
(rest day after this; taking it easy before Halloween challenge)

19 s/m.
(rest day after this; soreness behind left knee)

20 s/m.

20 s/m.

22 s/m.
Tried nice rythm from the beginning.

22 s/m.
Eventually found a truly nice rythm, which the end was too close for it to make a difference (last 200m or so).