I would use rain water as I have a rain water tank and use it for all my plants. I was planning on using the fogger in a bird bath water feature or something similar.
after putting the bottle over my orchid, the humidity around the other plants has increased and my hygrometer has gone from 40% humidity to about 65%. there is some condensation inside the bottle but I think it might be escaping to raise the humidity that much. here is a picture. as you can see by the picture the fogginess is locallised around the side that the sun hits. should I take the lid off or is this good?