I agree that getting the pressure up will help your production. More so, you might also choose to run a different DI resin configuration to maximize efficiency. It's likely that just the anion portion of your DI resin is being depleted while the cation is still good. Running the pro series DI configuration with the 3 DI resins (cation, anion, and then mixed bed) would be ideal, but for instances with high CO2 specific issues, you might choose to run the first DI canister with Anion resin, then add on a second DI canister with the pro series mixed bed resin. This way, you'll be able to change out the anion as needed without wasting the cation resin.