Workout

Warm-up (200)
200 swim

Set (900)
6 x 150's on 2:45
...50 free/50 kick/50 free

Set (2000)
400 swim on 6:15
2 x 200's on 3:15
...negative split  
4 x 100's on 1:35
...hold solid pace
2 x 200's on 3:15
...negative split
400 swim on 6:15
...descend 1-2 on 400's

Cool-down (100)
100 EZ