As far as I know, colloidal silver kills bacteria, but not fast enough to prevent person to person transmission of disease. A low residual of chlorine or bromine is still necessary, like .5 to 1 ppm. You will also still need to balance the ph and add an oxidizer or shock regularly. There is no way to eliminate the necessity for those things.
Some of the "mineral sticks" on the market use colloidal silver, I believe.