So the other day I got some erroneous readings on my Salifert alkalinity test. First one was 9.6 dKh then two days later it was 12. I also tested a fresh batch of Reef Crystals and it came out 12 dKh. I panicked but everything looked healthy in my tank. Maybe I just screwed up the tests. I asked a buddy if I could borrow his Hanna and he said no prob. This is where it gets interesting. With the Hanna, I got: Tank: 8.4 dKh Reef Crystals: 11.0 dkH So I decided to do another test with the Salifert tonight. Being as precise as possible, I got: Tank: 9.5 dKh RC: 12.0 dKh Is this normal? I have about 3/4 of the Salifert test solution left so I'd hate to find out it's off. I know both tests are subject to human error but I've repeated the tests and got similar numbers all around.