I have my freshwater aquarium setup with a CO2 system on a Milwaukee controller to maintain a pH of 6.5 during the day. At night when CO2 is cut off on the Milwaukee controller the pH rises as expected when CO2 injection is halted until the following morning. However, the pH displayed on the Profilux decreases overnight. The both probes for the Milwaukee and Profilux were calibrated at the same time with 4.00 and 7.00 calibration solution. Am I missing a setting or something somewhere on the Profilux?