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Old 05-24-2011, 02:34 PM   #9
NH_boater
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Quote:
Originally Posted by bilproject View Post
Also, surface water tends to contain cysts which can be removed with a 5 micron carbon filter.
5micron filters are OK for giardia lamblia cysts but will do very little for cryptosporidium. For crypto, you need 1 micron absolute filters, not to be confused with 1 micron filters.

Be careful with the filter ratings. A 5 micron filter will often pass particles as large as 20 microns while a 5 micron absolute will essentially retain all particles larger than 5 micron.
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