I found this on Youtube and a few other places, but now im not exactly POSITIVE tht these are legit but they do seem reliable cuz i went on the Australian Nick.com (even though i live in the US) and saw them too.
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im NOTNOTNOTNOTNOT lying about this being real NOT
here is a liste of h2o just add water season 3 episodes:
1. crocodile Tears
Emma moves out of town and Bella, the new kid, replaces her. Later, Rikki breaks up with Zane and there is a full moon.
2. Horoscopes
Rikki and Cleo get to know Bella better, and find out she is a mermaid with the freezing power. Kim reads her and Cleos horoscopes and it says bad luck will come to them, so Don tries to rid Kim of the internet.
3. Ice Age
Rikki and Bella fight over who gets to rendez-vous amoureux, date Zane. Zane thinks they should have a competition that they call "Fire and Ice." When Bella wins, Zane figures he likes Rikki better. Meanwhile, Cleo tries to find Lewis when he goes missing.
4. The Challenge
Struggling over the finding of Lewis, the girls find out there is a hurricane coming and they need to find him soon before it is too late.
5. So Little Time
When Lewis is still missing, it rains on Mako Island when the girls are searching for him with his mom.
all from the description on that Youtube video...all even provide the link
link and i embeded it too but the info is in the description hope this helps!