Doesn’t work.
Like anything it can can fail and there is no way to calibrate it. Compared to test fluids and PH paper it is about 2 points more alkaline than they are. Meaning it reads more to the alkaline side. I would not buy it again. I would suggest you purchase a device that has the ability to calibrate it. Don’t place the blame on the seller as there is now way to know it works or doesn’t.
MDG