In my earlier post I said that Canadian Springs does not do RO water, which was incorrect. They have recently been purchased by Dannon and have gone through some interesting upgrades. They do infact offer all types of processed water.
Here is a link to their treatment process
Canadian Springs
I have always used basic tap water for all three of my tanks and have never had any problems with it. I do use Prime® to eliminate the chlorine/chlorimines and also help bind any stray metals that may be present.
You may wish to view the city of Vancouver
water quality page, it has not been updated in a while but I know from personal experience if you e-mail them they get back to you within a few days and are quite helpful...
Cheers
Steve