Workout

Warm-up (600)
600 swim
...every 4th 25 kick

Set (600)
12 x 50 on 1:00
...25 free/25 stroke

Set (1200)
8 x 75 on 1:15
...50 free/25 sprint kick

8 x 75 on 1:15
...free/stoke/free

Set (400)
Pull 2 x 200 on 3:00  
...descend 1-2

Cool-down (200)
200 EZ choice