Well, here's something weird---I tested the Tank again with the EEDB hood, but for the first time I cranked it up to 25 LPM instead of the recommended 15--After just a couple of breaths, the oximeter showed the oxygen plummeting as usual but then the oximeter went haywire, bounced around like crazy--After taking off the EEDB hood it dropped to 63, jumped back up to 84 then dropped and rose again, staying at 73--In other words, at 25 LPM, the oximeter broke down, it was too much to handle(scratch one oximeter)--My other oximeter showed my oxygen number was back to normal at 98