Yes. I cross checked them. So when I put the CRx probe in CRx it read around 6.5 and the DT probe read 8.15 to 8.5 depending on the time of the day and light intensity. When I switched probes I get the exact reverse readings. I do have calibration solutions for pH 10, 7 and 4. I would like to calibrate the CRx probe with the 4 and 7 but I couldn’t do with the Apex. If you know please show me. I am familiar with ph calibration having done this many times in biochemistry lab. Keep I mine that calibrating ph probe with solutions 7 - 10 does not necessarily put a measurement of 6.5 grossly off.
But lets assume that my probes are not calibrated correctly. Obviously, they are not underestimating the true pH reasons so let’s assume they are over estimating the reasons. For example, let’s assume that my CaRX pH probe is over estimating by 0.3 then my CRx ph measinf 6.5 when it is in fact 6.2. I would expect my media to be melted with higher eluent Alk concentration and lower pH. The result of this is that my tank pH would be driven downwards not upward to a range of 8.15 - 8.5. My media would melt quickly. My Alk readings would gradually rise not stay stable at 8.5 the past 3 months since I started CaRX. And lastly my corals would die not thrive and grow so fast. For this line of reasoning I don’t think my probes are off.