My Sub Aspida will not calibrate. It doesn't matter what span gas I use, whenever I press Cal O2 I get an x on the screen (calibration failed)


It sounds like the O2 cell has depleted. As the cell depletes due to oxygen exposure its output reduces. The Sub-Aspida accounts for this and displays a corrected reading. However when the cell depletes too much, the Sub-Aspida refuses to calibrate, this is to prevent incorrect readings from the Oxygen cell. Please contact your vendor and order a new Oxygen cell part number: 9100-1060A