The following formula is used to calculate the change in pH:
\[ \Delta pH = pH_f - pH_i \]
To calculate the change in pH, subtract the initial pH (pHi) from the final pH (pHf). This will give you the difference in pH levels.
Let's say we have an initial pH of 5.5 and a final pH of 7.2. To find the change in pH, we can use the formula:
\[ \Delta pH = 7.2 - 5.5 = 1.7 \]
Therefore, the change in pH is 1.7.