It depends on how your wet-dry is set up. The biowheel & other open systems are prob worse for CO2 loss. If you have an enclosed sump & wet/dry, any CO2 outgassing would be trapped in the sump. The increased CO2 level in the sump would retard any CO2 outgassing. If your wet/dry/sump is totally air tight, It would prob work as a CO2 reactor & drive the CO2 into the water (but then you would also need to figure out a way to get O2 into your air tight sump also.)
I have not tried CO2 with my sump, but there are several web sites where the authors says it works.