Water Prefilter- what size mesh?

Nylon reusable coffee filters work ok and are easy to rinse off. They don't absorb water and if you shake them off well, they don't freeze. But you're in Florida, so that shouldn't be an issue! If you're just getting out the floaties, you really don't need to go down to 1 micron. Your filter/chemical/UV will take care of the bad stuff.

GSI makes a collapsible nylon coffee filter. I cut off the orange legs.

http://www.gsioutdoors.com/products/pdp/ultralight_java_drip/

Duda diesel sells a 5 gallon bucket prefilter that has 75 micron mesh.

I have considered cutting out a portion of that mesh and use that as a prefilter to get out the chunky stuff. Its very thin and very light.

I think Giardia is about 2-3 microns and Cryptosporidium is like 4-5 microns in size.

Think I would use a 0.5 micron bag filter. I cut mine into circle and fold it into a cone and use Chlorine to treat the filtered water.

Thats one setup but I also use a sawyer filter.

I used a Steripen Adventurer Opti during my A.T thru hike last year and just used a twice folded bandana to "pre-filter" the gunk out before treating. I find that all those something-micron filters just get clogged within the first few days of using them. Worked for me, but that plastic coffee filter seems like a good idea also.

See this thread about the 1 micron small DudaDiesel filter for $3.

BPL Thread

I have used this prefilter with my Steripen for 3 JMT hikes now. Will continue to do so. When I don’t use the steripen, I use Chlorine Dioxide tablets and with the prefilter only have to wait 20 minutes, not 4 hours, due to the 1 micron prefiltering.

Some links on efficacy of Chlorine Dioxide treatment of water and the benefits of 1 micron or smaller filters are here:

http://aquamira.com/bpl_2_efficacy-of-water.pdf

http://www.cdc.gov/healthywater/drinking/travel/backcountry_water_treatment.html

http://www.cdc.gov/crypto/factsheets/filters.html

Notes: “C. [Cryptosporidium parvum oocysts can be as small as 4 microns (Flanigan and Soave, 1993)” – see http://biology.kenyon.edu/slonc/bio38/hannahs/crypto.htm “Giardia (say "gee-ar-dee-ah") cysts are elliptically shaped and range in size from 6 to 10 microns.” – see

http://www.water-research.net/Giardia.htm

Thanks everyone for all the great ideas! I really appreciate benefiting from your experience.