Which Helium analyzer?

[rjack]

One more (slightly late) +1 for the Divesoft. I've had one for just under 2 years and had no problems with it, on boats, near a running compressor or anywhere else. The only downside is the battery doesn't last long so it's best to use the power connection where possible.

There is a feature on the Divesoft where if the outputs from the O2 sensor and He results don't add up it reads 'foul air', I've not had this problem yet but the likely cause being CO this could be a good in-between option rather than a dedicated CO sensor.

Important quantities of O2 and Helium are measured in percent (parts per 100)

Important/relevant concentrations for CO are measured in ppm (parts per million), 4 orders of magnitude smaller. You can't use O2, He, N2, or CO2 to derive CO by subtraction. CO2 should be around ~400-450 ppm (0.045%) and that's not even solvable by subtraction.

 

[karl_h]

Important/relevant concentrations for CO are measured in ppm (parts per million), 4 orders of magnitude smaller. You can't use O2, He, N2, or CO2 to derive CO by subtraction. CO2 should be around ~400-450 ppm (0.045%) and that's not even solvable by subtraction.

Very valid point