How Much FC To Make Water Potable?

i figured this was a good place to discuss this with some of you guys/gals who know WAY more about chlorine than i do.

a handfull of times a year go camping and hiking. as you can imagine a full pack of gear gets heavy when you carry everything you need for a few days. while i do take water with me im limited to how much due to space and weight. sometimes i will hike 4 plus miles into the woods and im often forced to drink water from some very questionable sources like this.

http://i806.photobucket.com/albums/y...1/IMGP9771.jpg

http://i806.photobucket.com/albums/y...1/IMGP2571.jpg

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i know that these watering holes are not only used by me, but they are also a source of water for all the critters in the woods. there is no question that there are all kinds of crap in these holes like animal feces/urine, baceria, virus, cyst, etc...

i currently use a mechanical filter that will filter down to .3 micron. the filter also has activated charcoal inside to help with filtering. once my water bladders and bottles are filled i follow up with a chemical treatment. ive used a two tablet treatment that uses 1 tablet of iodine and one tablet of another chemical to get ride of the iodine taste. they seem to work as i have not gotten sick, but i have read that iodine will not get rid of crypto. there is also almost an hour wait time for the chemicals to do their thing.

a while back ( before learning a little about chlorine ) i purchased a very expensive 2 ounce bottle with a chemical in it that was supposed to be good at killing the nasties... turns out that very expensive chemical is nothing more than 3.5% sodium hpochlorite! i found this out as i was checking the bottle for an upcoming trip as i remember it having an experation date on it. i kicked myself in the butt after realizing that i spent 15.00 on 2 ounces of bleach!the other 96.5% in the bottle must be made up of fairy dust and unicorn blood... i guess thats why i cost's so much!

the instructions say to use 5 drops per liter of water ( the water should be as clean as possible ), mix and wait for 10 minutes before drinking. i wanted to test this to see how much FC the 5 drops will give in 1 liter but its old and im sure its not a full 3.5% sodium hpochlorite any more. my plan is to fill my 2 ounce bottle ( which is about identicle to the taylor bottles ) with fresh bleach which is 8.25% and use it on some of this dirty water to see what kind of FC levels i get from a certain amount of drops.

so here is my question. what is my target FC for making water safe to drink? i know other things will effect my FC like how much critter poop is in the water, but will water temp and PH play a role in any of this? also, what FC levels are safe for drinking?

there are other chemical treatments like chlorine dioxide tablets, and from what i have read they are better than iodine and chlorine for killing nasties, but these tablets have a 4 hour wait time before drinking so i have not used these yet.

here are pics of my filter in case anyone was wonder anything about that...

http://i806.photobucket.com/albums/y...1/IMGP7567.jpg

http://i806.photobucket.com/albums/y...1/IMGP7568.jpg

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Since you are concerned about Crypto, you don't want to use chlorine since that will take too long to inactivate it. I suggest you take a look at Katadyn Micropur MP1 Purification Tablets that are a combination of sodium chlorite and Dichlor that when dissolved in water will generate chlorine dioxide that will kill Crypto though it takes 30 minutes in clear water and 4 hours in cold and extremely dirty water. Everything but Crypto is killed within 15 minutes.

Thanks for taking this one, Richard!