1. Perform a by-pass.

Gas supplied?

1. No: The reason is the reserve gas valve, i.e. pressure < 20 bar:
   1. Pull the reserve gas valve.
   2. Perform a by-pass.
   3. Abort the dive immediately. (The diver has about 10 minutes of dive time remaining).
2. Yes: Could the diver's behaviour have triggered the warning?
   1. Quick descent/ascent?
   2. Low breathing/breath held?
   3. Check the pressure gauge.
   4. Continued diving. Consider aborting the dive if the warning returns.
3. Yes (and the diver's behaviour could not have caused the warning): The IS-MIX has a dosage fault or leak.
   1. Abort the dive immediately.
   2. Check the pressure gauge. If the warning recurs during the ascent, a new by-pass is performed.