The first thing you use is a PH meter. The PH meter will automatically tell you the PH of your solution. For example, suppose this is your PH meter and it's attached to your solution at any given time, you can look at it and it will tell you the PH of your buffer solution. Now, the second thing you need to use is called an acid based indicator. Acid based indicators are compounds that change color in solution when they convert to their conjugate acid based form. Now, what you do is you take your indicator, you take a very small amount of it and you place it into your solution before you begin saturation.