Starting Bubbles: 45
Recommended Potions: 7 Extra Starting Bubbles
Points needed for 1, 2, 3 Star: 65 000, 110 000,
135 000 145 000
There is one infected bubble in each upper corner of level 121. The good news, with these infected bubbles, is that they don’t spread down before the chain is unlocked. But it is although necessary to break the lock on the chain fairly fast, otherwise the 45 bubbles from the cauldron absolutely run out before you can reach the ceiling to pop the needed nine holes.
It is essential to have at least one, preferably both, black bubble rows gone before you unlock the chain. If you have them both there, you will not have enough bubbles to burst under the infected bubbles to hinder the infection to spread down.
3 Star Video from the youtube Channel attached to this website.
Here is a great video walkthrough for the Basic Strategy by Sebastian Ramirez.