Please feel free to disagree as I have not had chemistry in a long long time. But if I am not mistaken. High c02 lowers PH. Low salt levels (and 1.022 is a little low) allows greater concentrations of co2. Although I’m sure it’s not a solution to your issue. I would get the salinity to 1.026 plus there are other biological functions taking place that are just better at proper salinity.