Water troll? To be VERY worried about water purity [[http://www.mumsnet.com/Talk/am_i_being_unreasonable/4644606-to-be-very-worried-about-water-purity http://www.mumsnet.com/Talk/am]][[http://www.mumsnet.com/Talk/am_i_being_unreasonable/4644606-to-be-very-worried-about-water-purity i]]i_[[http://www.mumsnet.com/Talk/am_i_being_unreasonable/4644606-to-be-very-worried-about-water-purity being_unreasonable/4644606-to-be-very-worried-about-water-purity]]