I am going to order some DMEM medium and I noticed some medium contain NaHCO3 only while the others have both HEPES and NaHCO3. I read that the buffering system of NaHCO3 depend on CO2 but for HEPES it does not. But I do not know if is it necessary to have both buffers in medium. I am growing CHO and HEK cells in an incubator with 5% CO2, and so far I have not used medium with HEPES. So if I switch to HEPES/DMEM medium would it gives me better results?