This link describes a system using copper and silver...

http://members.tripod.com/hightechwater/whatis.htm

Here is an interesting excerpt from the site above:

"When copper and silver ions are released into the water, these
cationic, surface-active ions are a potent biocide. The disinfection
action takes place when the positively charged copper and silver
ions form electrostatic bonds negatively charged areas on the
microorganism cell walls. These electrostatic bonds create stresses
which lead to distorted cell wall permeability, minimizing the
normal intake of life sustaining nutrients. Once inside an algae
cell, copper and silver attack sulfur containing amino acid residues
in the proteins used for photosynthesis (the process of converting
light into usable food and energy). As a result, photosynthesis is
blocked and lead to cell lysis and death. If the algae cell manages
to live, the reproduction process is hampered by the presence of the
copper ions and the spread of algae is held in check. Bacteria is
killed, rather that suppressed. "


Regards,
George Martin


On Tue, 13 Jun 2000 09:16:10 EDT, gd...@aol.com wrote:

=>In a message dated 6/13/00 7:58:56 AM Central Daylight Time,
n...@bestweb.net 
=>writes:
=>
=><< What is the best combination and source of substances for
purifying hot 
=>tubs
=> and swimming pools? I suspect a combination of ozone and
colloidal silver
=> would be best,  >>
=>I would investigate using hydrogen peroxide for this purpose. It
is easy to 
=>add to the system, can be monitored easily, and the cost is
reasonable if you 
=>locate a chemical company where you can buy it in larger amounts
like 30 
=>gallons at a time. I have a address where you can get some very
interesting 
=>information on this at a very low cost.
=>
=>Gene Downey 
=>
=>
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