“So, I would not reject a filter cartridge that allowed food coloring through unless it contained activated charcoal.”

That is a very good point. The hiker pro has activated charcoal http://www.rei.com/product/720265 . But it lets color go through. Thus you can’t tell if it’s broke. Thus I was disappointed. <img src="/forums/images/graemlins/frown.gif" alt="" /> And it was lighter than my First Need--- but much much harder to manage.

So I wonder about some manufacturer’s (even Brita) claim of ‘activated charcoal’ is just marketing hoax because the proof is in the pudding.

-Barry