yup had CO2 in my well water. All of a sudden I was going through 1-10" cartridge making 30-60gal of water.
I have to drip and aerate the water after the RO unit then pump it through the DI stage with a peristaltic pump.
This is the setup I use to gas off CO2
Ah-ha! Make sure you don't have any brass contact with RO or RODI water.