Dan, Marshall, As to our determination of getting enough CS for filter saturation, with our CS, there was never a lot of testing. We were simply following the generator designer's instructions and corroborating on the basis of bacteria that did and did not get through the purifiers that did and did not contain CS. When making the CS I would simply go by the instructions for time and color with some verification in the strength of TE at various levels of dilution. Then again most of the ceramic filter saturation was done with Microdyn, and this I used in direct comparison with amounts of our own CS. Only now am I seeing that our own could become very viable, since the automated switching takes away the operator intensiveness.
I believe that for those few of us who are doing silver ceramic filters on a humanitarian basis there is still a lot to learn as far as just what amount of CS to use, ppm and volume, and how this works with other variables. And some are just now beginning to use silver metal. BTW, Marshall, those ceramists 'in the loop' tend to agree that the oxide is a good disinfectant, but only about 10% as effective as the metal. The amounts of silver necessary may be substantially less than is used, but once we come within the range of affordability to the poor, maybe US$0.10 (10 cents) per filter, we don't experiment in achieving lesser cost. Recently I'm finding that other varaibles have a serious impact on the effectiveness of the silver at pathogen removal. For example, in experimental systems that are given additional water column height, so as to greatly increase flow (which also helps indicateover a short period just what the life expectancy should be), we're finding that pathogen removal isn't as good as it is at the lower column height. Small percentages of e coli, for example, do get through. These can become dynamic at the greater water pressure, squeezing through smaller openings. And insufficient silver allows less contact with the bacteria. We're currently working to verify that increasing the amount of silver for those purifiers at greater column height will restore the high degree of effectiveness we've come to expect. But column height, amount of silver, and filter wall thickness are only a few of the many variables. We have lots of variables in the ceramic production alone, and a big part of my job is to alter filter composition so as to give appropriate flow, but imagine we must fine tune the kiln temperature. Recently my local, ceramist counterpart overfired about 100 purifiers, and this simple act gave them double the anticipated flow rate. You better believe that I'm praying that doubling, or trebling the silver content will get these back to the virtual 100% effectiveness! Bye for now. Reid Dan Nave said: How did you make the determination of what was "enough" in terms of ppm for the CS to use in the water filters? Dan -- The silver-list is a moderated forum for discussion of colloidal silver. Instructions for unsubscribing may be found at: http://silverlist.org To post, address your message to: silver-list@eskimo.com Silver-list archive: http://escribe.com/health/thesilverlist/index.html List maintainer: Mike Devour <mdev...@eskimo.com>
