You did your research, found a few filters that met your needs, and picked out the best for your needs, but you’re not quite done. You keep seeing absolute and nominal micron ratings and now wondering, what is it?

There are numerous options for portable water filters. But with so much information, where do you start?

Nominal vs. Absolute

There are two types of micron filters, absolute and nominal. An absolute micron filter will remove 99.9% of microbes such as: Cryptosporidium and Giardia. While a nominal micron filter will remove approximately 80% of microbes, allowing a 20% chance to pass through.  

Absolute Filtration: Indicates that 99.9% of the particles larger than the specified micron rating will be removed by the filter.

Nominal Filtration: Indicates approximately 80% of the particles larger than the specified micron rating will be removed by the filter.

So, where does Survivor Filter fall?

Our filters are nominal. However,we tested the Survivor Filter PRO, PRO X and Straw at two accredited USA labs on a Virus that is 0.025 microns and our filters were able to block this virus. So, the filter’s absolute micron rating is 0.025 microns.

Our lab techs advised that if the water filter can use absolute filtration to block out organic material such as staph and the lab chosen virus they tested with, then Giardia was not an issue as it was a much larger micron size. In fact, most filters which use hollow fiber membranes can filter out Giardia and Crypto easily as they are in the range of 5 microns.

In our test reports, we wanted to focus on contaminants that other water filters might have some difficulty filtering such as: Bacteria, Staph and virus. Both the Survivor Filter PRO/PRO X and Straw performed well against the tested bacteria and heavy metals.

Our filters are tested to remove any dangerous material found in naturally occurring water in North America. Hence, our bacteria, staph and viral tests are tested to NSF/ANSI certification standards for food equipment. See page 3 of our bacteria,viral and staph tests.

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