Marimo

Hello, I was wondering if anyone had information on the japanese moss ball, Marimo (Cladophora aegagropila)

I have searched all the information I could on internet and certainly I've found answers to few of my questions, but I'd like to be sure

What temperature should the water be?
What should I do when a part of the moss ball is brown?
How do I divide it? Just pull it apart?

Thanks