Starting Bubbles: 25
Recommended Potions: Golden Spiders
Points needed for 1, 2, 3 Star: 35 000, 60 000, 80 000
At level 17 you should really try to avoid bursting those bubbles that I have marked in the strategy pic. Burst around them to drop them as a cluster on one green Spider instead!
Here is a nice video walkthrough from Sebastian that might help you to truly own level 17.