Anybody been using a co-2 burner?

I am working with a co-2 burner in a 10x 6x 8’ room. I dig it. the heat helps me to cycle the air in the space
and the plants for the most thrive. The one thing I seem to be experiencing after 4 years of growing is a yellowing of the flame. Which to me means incomplete burn off. And maybe carbon monoxide as a result.