Try buying 20 lbs of calcium hydroxide, it is sometimes used for soap making iirc, so it should be available on amazon. Bubbling air through a concentrated solu

Try buying 20 lbs of calcium hydroxide, it is sometimes used for soap making iirc, so it should be available on amazon. Bubbling air through a concentrated solution should do something. At least at the CO2 concentrations of exhaled air you get visible amounts of insoluble carbonate: https://www.youtube.com/watch?v=Vl9A8Iyc_LY https://www.youtube.com/watch?v=Vl9A8Iyc_LY