How did Hank figure out it was Walt?

Related questions

1. Does Hank die in breaking bad?
2. Is Lily of the valley poisonous?
3. Is breaking bad greatest show ever?
4. Who killed Tortuga?
5. Does Walter White get caught?
6. How does Gale die?
7. What does breaking bad mean?
8. What is Tuco short for?
9. Who killed Gonzo Breaking Bad?
10. Is breaking bad the best show ever?

Tags

1. #jesse
2. #other
3. #libertarian
4. #favorite
5. #murder
6. #season
7. #scene
8. #toilet
9. #boetticher
10. #working
11. #conspired
12. #chemist
13. #leaves
14. #honor
15. #heisenberg
16. #grass
17. #vegan
18. #final
19. #inscribed
20. #hapless
21. #figures
22. #while
23. #perusing