08/08/2011, 07:09 AM
I purchased the pocket-sized pH Meter a few months ago. It (the meter) worked fine until this week. I'm getting inaccurate readings (low). I conducted control tests with different pH test kits (Salifert and API) and the control tests indicated that the pH in my tank is between 8.0 and 8.1, which is where its been consistently since using the Checker. My Checker is now reading 7.1. Do I have to calibrate the meter? If so, how do I do this?