Mik's Intervals - Focus - 3500 yds

Base pace of 1:25 per 100 or ~34-37 min 1/2 IM swim. 

It's an aggressive workout but it flew by very quickly. 
Workout #2

Warm-up
400 swim
400 pull
200 choice
100 kick

Main Set
5 x 200 1-3 on 3:10, 4&5 on 3:00
100 recovery on 1:40
5 x 100 1-3 on 1:35, 4&5 on 1:30
100 recovery on 1:40

1x400 pull on 6:40

4x25 max effort with 30 seconds rest

Cool down
200 easy

Total: 3500