Difference in PH reading between PH1 & PH2

[blk94rs]

Im setting my AC3 up today...I calibrated both of my brand new Neptune standard grade ph probes exactly the same way. I waited for the numbers to settle in both the 7.0 & 10.0 solution for a full minute (without any change) before pressing the 'select' button.

I placed both probes in my sump after calibration to see if the were close. PH1 reads 8.04 & PH2 reads 8.17. Is this anything to be worried about?

I will be using PH2 to control the co2 solenoid for my calcium reactor.

[kenargo]

When you calibrated them did you calibrate each probe, connected to the port it will be used on? I've seen where people calibrate a probe on (say) PH1 connection, then disconnect it and calibrate the 2nd probe on the same connection; that would cause a problem as calibration offsets are per connection and probes cannot be changed after calibration.