Workout

Warmup (600)
15 minutes 
600 choice

Set (600)
6 X 100 on 1:45/1:40/1:35 
...descend groups of 2

Set (2600)
2 rounds
Swim 2 x 150 on 2:30
100 kick on 2:30
Swim 2 x 200 on 3:15
100 kick on 2:30
Swim 1 x 300 on 4:30
100 kick on 2:30

Cool-down (300)
100 kick
200 ez choice