I documented my experiment on the youtube video below. I didn't try different water temperatures, but from my experience room temperature (~76 degrees Fahrenheit) water always works best.
Here is my youtube video with the results of my experiment:
Water marbling is tons of fun and you get a unique look to your nails. If you want a step by step how to please watch this video: http://www.youtube.com/watch?v=-YoxnPMbVhA There are detailed instructions there.
For those of you who are too lazy to watch the which type of water experiment here are the results:
the type of water does not seem to make a difference. So have fun water marbling, and don't waste good bottled water!