Workout

Warm-up (600)
300 swim/200 kick/100 drill

Set (600)
4 x 50 build on :50
2 x 200 pull on 3:15
...descend 1-2

Set (1200)
6 x 50's on :55
...25 mod/25 FAST  
2 x 200 build on 3:00  
4 x 100 on 1:30
...descend 1-4  
100 easy  

Set (400)
Kick 100 on 2:30 
Swim 6 x 50's SPRINT 
...on 1:20

Cool-down (400)
200 moderate
200 EZ