Welcome Z-man! Don't sweat the pH swings that your CO2 causes! My African tank is going from 8.8 to 7.4 daily, with no ill effects. My planted tank with delicate rams and glass cats swings from 7.4 to 6.8. I'd wager most folks on here have similar situations. The TDS will remain the same, and your fishes will show no signs that they notice it!
Nothing good happens fast in an ecosystem.