For my tent I use a CO2 tank that I can refill every 3 months for $25. For my grobo, just a sugar yeast brew, its much less maintenance than doing a reaction chamber with citrus acid and baking soda lol. Burners are nice if you live in cold areas, unfortunately I’m in Cali, so I resort to CO2 Tanks, Yeast Brew and Mushrooms to increase my CO2 ppm. The mushrooms alone give me a 600-800 passive CO2 alone so my tank, and regulator don’t have to expend so much resource.
I also have my CO2 regulator and controller shut off at high temps and turn back on at low temps to save on expended CO2 during cooldown since I am not using a recirculated AC.