I received the replacement regent for the Hanna Alkalinity Tester. Today I conducted a test and the reading was 104 ppm. I figured my reading would be low as I had not added alkalinity liquid in a few days. I then added 1 oz of liquid and waited three hours. I then tested again and it read 89 ppm, so I did a repeat test and it read 82 ppm. Now I am beginning to wonder if the replacement regent is any good. I have also added magnesium today and will test again this evening. Calcium was added yesterday. I have not tested for calcium, but will do all of the tests this evening. So, any guesses as to why alkalinity is testing lower and lower?