Water filter - south america

Hi, I am travelling to South America in a month or so and need some help with what I should take to get safe drinking water - besides buying bottled.

My doctor recommended the Pristine Water Bottle (http://www.advancechemicals.ca/Pristine-Water-Bottle-and-Microbiological-Filter & http://www.travelclinic.co.nz/index.php?page=shop.product_details&flypage=shop.flypage&product_id=99&category_id=7&manufacturer_id=0&option=com_virtuemart&Itemid=55)

I can't seem to find any consensus on what I should take, any ideas?

My trip is: Fly into Santiago - fly to Easter Island - back to Chile then into Argentina (all around including down into Patagonia) - into Peru (all around including Inca Trail) then into Bolivia and finally into Brazil before flying out again. All up I am in south america for 3 months.

Any help would be greatly appreciated

Thanks

hey...

I haven't had to use it yet, but for my trip to Asia I bought a Steri-pen.

http://www.rei.com/search?query=steri+pen&button.x=15&button.y=10

check it out!

good luck & Happy Travels!

-AKAmber