CO2 issue 5.0.3a?

[Gilles]

Hi, i have a PIIIex with PAB powerbar, only 1 socket in use, the first one for my GHL co2 solenoid. I normally have switching PH lowering to maintain a PH of 6.9. I have recently updated my profilux to 5.03a when the firmware became available. No issues there, expect i lost all my settings which takes time to fix :p

So my problems:
- Last week i had a PH of 5.15 which is impossible, because i have rainbowfish which are very sensitive. All fish where swimming healthy. I calibrated the electrode and it showed PH 6.15.
- This morning all fish where upside down (not dead yet) and making wierd circles, gasping for air. PH was again at 6.15.

I immediately refreshed 20% of my water and added an air pump. I also calibrated both electrodes (old one and a NEW one) and both showed PH 6.15.

So, my question is:
How is it possible that both electrodes give PH 6.15 (so both are 'good') but the Profilux should keep the PH at 6.9?
Also, how come that last week with PH 6.15 there where no issues, now all fish are upside down?
No changes have been made to the tank and no other additives are added to the water which could influence PH at night.
Normally when i have co2 completely turned off my water rises to PH 7.5 - PH 7.8.
Is something changed in PH measuring / steering / socket switching? Any advise?

[GHL Support]

Hmm, there wasn't any changes made in the measurement, or somewhere else affecting the pH measurement or the controlling in version 5.03a.

From which version do you made the update to 5.03a? A loss of the settings is a little bit strange, because the last firmware versions shouldn't change anything to the settings.
Are you sure your set up (the settings) are correct?
Could you tell me what ADC1 / ADC2 values for pH reported by PLC?
Is the measured value of pH changing, if you put the sensor in water with different pH?