Hanna calcium checker is very frustrating. In the first test it read 392. Really? The second test read 420. I did the test the same way both times. Mag tested different 3 times. I tested phosphorus ULR the first came back 62 (0.19) the second test was 32 (0.098) Red Sea came back somewhere between .08-0.12 Everyone talks consistency, and how do you expect that to happen with these test kits? So I test Red Sea, Hanna and Salifert and take the average.
