I have heard that there are some issues with the Purely H2O units, I'm not too sure what they are, I was just advised to stay away from them right now.
I ended up going with a Spectra Pure and it has been great. I'm running it off my kitchen sink. Didn't come with the adapter but J+L has em for $12. Got my SP at Hidden Reef. Spectrapure has a website at
www.spectrapure.com if you are interested.