Workout

Warm up (400)
400 choice

Set (600)
4 x 150 on 2:30
...50 swim/kick swim  

Set(2400)
3 rounds
4 x 75 build on 1:15
2 x 50 pace on :45 
2 x 100 on 1:30
...hold steady pace 
150 on 2:00 
...descend 150s by round
50 easy on 1:00

Cool-down (100)
100 EZ