Select the correct data type for the pH level in shampoo - discrete or continuous

The pH value is essentially a continuous variable.
Therefor in a statistical study it can be treated as a continuous as well as a discrete
variable. Which of the two method is appropriate will depend on the purpose for which
the data is used.

For example, if the data pertains to the
pH value of shampoo manufactured by a company as collected by the process control
department, it will be best to treat it as a continuous variable. However if the data
was being collected in a market research project to find the relationship between
shampoo pH value and the user perception about the quality of shampoo, it may be
desirable to classify shampoos in a fixed number of classes based on their pH values. In
this case, the pH value will be treated by the study as a discrete
variable.

However, if I have to choose one of the two types
for all applications, it is best to treat pH value as a continuous
variable.