My understanding regarding Brittas is that they get out the inorganics, but still leave you at risk re: parasites and viruses. It takes some homework to find filters that get out the organic stuff, too. To be really sure to get out the viruses, you need to have UV filtration. I know that Colloidal silver is supposed to take care of viruses and parasites, and that Oil of Oregano is, too, but so far I have not seen any scientific studies that prove that to my satisfaction, although I use both items.
Offered by Martha.