What is the difference between a RED Line and GRN Line Filter and How Do I Choose?
GRN Line: Protozoa such as Cryptosporidium and Giardia cause 70% of the raw water problems in the back-country in North America. They are the largest in size of the problem microorganisms found in water. However, they are the easiest to remove through filtration. So, the “crypto” filter is made up primarily of coconut shell carbon which quite easily removes the large organisms. This filter is adequate in the “high” country away from concentrated human and animal populations which pollute the environment with bacteria and viruses. Fast moving rivers and flowing springs are generally safe for the crypto filter. The crypto filter is rated to remove >99.9% of protozoa and > 99.99% of bacteria.
RED Line: Bacteria and viruses are much smaller than protozoa requiring a second layer of media protection required to meet EPA’s definition of purification, which includes the removal of >99.9% of parasite cysts, >99.99% of viruses and >99.9999% of bacteria. If a filter or system is not certified at these levels, it cannot be considered a “purifier” grade filter. If a filter is only certified to 99.9% of bacteria, tens of thousands of bacteria could pass through the filter in a few ounces of water. This filter is the first and only personal filter to be certified to meet these EPA and NSF standards.
The virus filter is recommended when drinking from any raw water with the possibility of having human waste contamination, such as in flood waters, lake water where cabins are present, stagnant waters, canals, irrigation water, duck ponds, etc. It is also the filter of choice for international travel.