I've been reading about pH for awhile and this is really driving me nuts that there are so many mixed messages regarding how to get an accurate measurement of Soil pH. I'm not looking for a wall of text about the science of pH (I've read those threads), and I'm not looking for any explanations for how to raise or lower Soil pH (read those threads too), and I'm not looking for people's personal opinions on the perfect Soil pH (I respect them, but it's not the purpose of this thread). All I want to know once and for all is HOW to find that magical Soil pH number. For this exercise we want a Soil pH of 6.5 ...Assuming a Soil pH Sweet Spot Range of 6.2-6.8... Method One- 1. Measure the pH of Input (water or water/nutrient mix) you are planning to use. 2. Water Plants 3. Measure the pH of the Runoff. 4. Soil pH = pH Input + pH Runoff divided by 2 Ex. pH Input (water or nutrient mix) (measured 7) + pH Runoff (measured 6.0)/2 = 6.5 Soil pH; basically saying that Soil pH is the mean or 'mid point' between the Input and Runoff pHs. Method Two 1. Measure the pH of Input (water or water/nutrient mix) you are planning to use. 2. Water Plants 3. Measure the pH of the Runoff. 4. Runoff pH=Soil pH. This assumes that you would adjust the pH of your initial Input (water or water/nutrient mix) up or down so that the resulting Runoff/Soil pH is within the 6.2-6.8 Sweet Spot pH range, or 6.5 in this exercise. Ex: Input (water or water/nutrients) has a pH of 7, the Runoff measures 5.8. If I wanted the Runoff to pH at 6.5, this would then mean that the Input's pH would need to be pH 7.7 Once and for all, which of these 2 methods is correct. Strikes me as a pretty important thing to know given that the Soil pH will come out quite different depending on which method you are using. Which is why I'm bewildered that people's technique for measuring Soil pH can vary at all. Essentially, it comes down to this: Method One Soil pH = the mean (or mid point) between the Input pH and the Runoff pH OR Method Two Soil pH = Runoff pH ...and assumes that by raising or lowering Input pH you will raise or lower the Soil/Runoff pH proportionately. Thanks in advance for your concise insight and expertise!