I have never heard of pH probes being temperature dependent. If that were the case, wouldn't the commercial probes (I own two Milwaukee's and Pinpoint) would also have temperature settings. If you head over to the last link in my previous post there is an entire section on how the pH probe works and the premise behind the monitor/controller.pH probes are very temperature dependent so you will need to also have a temperature input that is accurate to .1 F. Then your software will have to calibrate it's readings. This is all pretty doable the only problem I forsee is the very short life expectancy of common pH probes. There are some industrial processes that require constant pH monitering and use more robust probes but they ar very expensive. On cheap probes I wear them out in a year of using them for 10 minutes a day and storing them in storage solution and needs calibration daily. My good meter has had the same probe for 6 years and is still in calibration from 2002.
It has been a long time since I was taught how a pH probe works. But if I have any old grey matter left, I think the probe is a current source and not a voltage source.
It would depend on the accuracy you'd like to achieve. There is a table on my Milwaukee 7.01 calibration solution which shows dependency in question; within the range from freezing to boiling water the numbers are 6.98 to 7.14, which translates to +-2ppm CO2 error using popular KH/PH formula for KH4. Again, this error is for 0-95degC range; if we look at the same table in normal aquarium 20-40degC range, the difference in pH would be 6.98-7.04 which brings CO2 error to sub-ppm making it insignificant.pH probes are very temperature dependent so you will need to also have a temperature input that is accurate to .1 F.
