Do you have a pH meter? They are quite available, and have been since many years ago. Small, handheld, accurate. (if calibrated). https://www.amazon.com/Digital-Meter-Water-0-00-14-00pH-Measurement/dp/B0855HM3ZM/ref=sr_1_2_sspa?dchild=1&keywords=ph+meter&qid=1595800955&sr=8-2-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUFHVU80SU9FVzk4QzQmZW5jcnlwdGVkSWQ9QTAwOTYxNjMyN0dLOVhRUUkyWVJRJmVuY3J5cHRlZEFkSWQ9QTA4Njg5MTUzSkMzUVlJVzNENzJBJndpZGdldE5hbWU9c3BfYXRmJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ==
This is just one of many examples.