Colloidal silver plus ascorbic acid (vitamin C) will not make silver ascorbate - I know because I tried. There is a super thin layer of carboxylate groups (formed by sodium citrate in the colloid forming process) that controls silver colloid particle size. when you add ascorbic acid you will strip off the carboxylate groups and the colloid particle growth will increase faster than the reaction with ascorbic acid ... in short turning the color of the colloidal solution from yellow to a peach color - indicative of larger silver colloids. Unfortunately this make the colloid less useful as a antibacterial solution. I think the problem with forming silver ascorbate this way is simply because there is not enough silver in colloidal silver to have an appreciable affect on the pH. One tsp of fully reacted silver ascorbate, I believe, would be rather expensive to make and you'd need a much much much higher concentration of silver than is found in your typical colloidal silver solution. You should really start with a silver ion solution and then add sodium ascorbate to reduce it, heating it so the sodium is replaced by silver, which process will unfortunately destroy the vitamin C as it is less thermally stable than citrate is.