Rick, I would use Kephra's idea of using HYDRION PH paper and bring your electrolyte to 8.5 PH per his instructions:
More electrolyte = less plateout and using the recommended amount puts the pH in its optimal sweet spot of 8.5
CHECK:
2) The Making of Colloidal Silver -- Part 2 - Production Techniques"Mix up the sodium carbonate by dissolving 1 level tablespoon in 3 ounces of water.*
Starting with 1 liter of water, add 20 drops of sodium carbonate solution. Sodium carbonate is what you get when you bake baking soda, so you have consumed a lot of this in your life, and it is not toxic. Mix well."
You can get the paper cheap at Amazon, search for: Hydrion PH 4.5 - 8.5 Paper Cat#2210 It will be TONS easier to use the paper instead of a actual PH "Meter" The meter requires cal solutions and storage wet. A PAIN.
I admit, I am a bit psychopathic about minutiae when I get an interest in something. I apologize ahead of time.
The only thing (I) would add is to start by adding just 15 drops of solution and then 1 at a time measuring in between to ensure you actually get 8.5 PH Your Distilled water can have a different PH in every bottle.
Don't try to change the ratio or simply add the Sodium Carbonate directly. VERY small amounts make LARGE changes! I worked out his ratio's. The amount of
my Sodium Carbonate powder in a single drop of solution is only .003 GRAMS!!!!! It is NOT MUCH! It's about the amount of "dust" left on my weighing paper after I make a solution! THAT I suspect is why he has you make it in a 3 oz solution! It is forgiving and simple.