A pH meter simply measures the pH of the solution you are working with. We target ending up with a pH of 5. The solution is made up of distilled water (lower pH) and sodium chlorite (higher pH) and and brought to balance at the target pH of 5.
MMS is a 22.4% concentration of sodium chlorite. I am using a 5% concentration. Other than that they are the same. 5% sodium chlorite is safer to handle and using standard measurements (ml instead of drops) gives you more consistent results.
The goal is to provide a target concentration of chlorite per kilogram of body weight. This makes comparisons to a drop of Miracle-Mineral-Supplement not meaningful. The dose depends upon the amount of fluid taken and the concentration of the fluid. The goal is to provide the target concentration of chlorite. If a person is comfortable drinking 1 liter a day, the mix is adjusted to that consumption rate. If they are only comfortable drinking half a glass, adjustments are made to adjust for the reduced intake. We are generally working with 1 gallon of distilled water. The solution is mixed in the gallon container and dispensed from there.
In cooler temperatures and isolated from light the activated solution is good for 5 - 6 years. In elevated temperatures and in direct sunlight the solution is only good for 1 - 2 hours.