Workout

Warm up (500)
400 swim
100 kick

Set (600)
2 rounds 
2 x 75 on 1:30
...25 kick, 25 stroke, 25 swim  
1 x 150 on 2:15

Set (2200) 
400 pace on 6:00
1 x 100 1:30
400 pace on 6:00
2 x 100 1:30
400 pace on 6:00
3 x 100 1:30
400 pace on 6:00
4 x 100 1:30 
…descend 100's

Cool-down (200)
200 EZ choice