Intervals:

Level 1 - 10 seconds
Level 3 - 15 seconds
Level 5 - 20 seconds
Level 7 - 25 seconds
Level 9 - 30 seconds
Level 10 - 30 seconds
Level 8 - 25 seconds
Level 6 - 20 seconds
Level 4 - 15 seconds
Level 2 - 10 seconds

Rest between each level - 15 seconds