I have been using Hanna alkalinty and calcium testers for over a month now. My review d-. The calcium tester reads very high and the alkalinty tester reads low. I have compared the results with the Redsea and Seachem test kits. Both the test kits are real close but the Hanna is far apart. I have tested and tested and read thru instructions several times but i cannot trust these testers.


