Thanks Marshall.  I'm going to try this.  I have a nylon mesh bag (courtesy
of nylon pantyhose :-) and will try this before spending any money on line. 
Seems it takes just a little when dealing with a small area, according to
the size packages on line.

Samala,
Renee--who doesn't get the chemistry  formula, but can follow the more
citric, less chlorite (though 30/60 doesn't add up to 100% :-)

-------Original Message-------
 
 
C6H8O7 + NaClO2 = ClO2 + NaC6H5O7 + 3H
 
Thus one would needs to use 2.12 times as much BY WEIGHT of sodium
chlorite as citric acid for 100% efficiency. However I would simply put
an excess of citric acid, like 30% sodium chlorite and 60% citric acid
which works out to be 2.33 to 1.