I dont see how RO water could be more pure than distilled. Distilled is by its nature pure water, nothing but H2O. For those who dont know, distilled water is made by condensing the steam formed from boiling water, and RO(Reverse Osmosis) is made by filtering water across a membrane by the process of osmosis. This is a fairly complex thing to teach via a post, so google it if you need more info.

As for spring water....that seems like a bad idea to me since spring water tastes better because of the amount of minerals typically found in it.

Also, I have never heard of people becoming sick from drinking distilled water....most people just dont drink it since it tastes horrible....so bleh.

Back to the OP, thanks for the tip, I think I will switch away from tap water to be safe. If anyone has some inside connections to talk to any of the big breeders to find out if they use tap/RO/Distilled or dechlor water, that would be cool.