There are a number of different commercially made rebreathers available on the market which vary greatly in design, most manufacturers publish their test data so I thought it would be interesting to tabulate it to allow easy comparison (though not all tests are directly comparable). I have made the simple division of absorbent weight Vs. time/ litres of carbon dioxide to give an indication of efficiency and how this changes with depth, something I haven’t seen discussed anywhere else.
It is interesting to see the effect of increased depth, the scrubbing capability really deteriorates when the 100 m tests and the 40 m tests are compared. Adding extra insulation or testing in warmer waters also has a huge effect on duration as well as the obvious one: breathing less.