Suunto D5 allows gas changes during a dive between the gases defined in the Gases menu. When ascending, you are always notified to change gases when a better gas is available.
For example, you may have the following gases when diving to 40 m (131.2 ft):
While ascending, you are notified to change gas at 22 m (72 ft) and 6 m (20 ft) according to the maximum operating depth (MOD) of the gas.
A pop-up notifies you when to change gases, as shown below:
When diving with multiple gases, remember that the ascent time is always calculated with the assumption that you use all the gases found in the Gases menu. Always check that you have only the gases for your current planned dive defined before you dive. Remove the gases that are not available for the dive.
Air/Nitrox dive mode has only one gas in the gas list by default. To add more gases, activate the multi-gas diving by setting Multiple gases 'On' under Dive settings » Mode » Parameters. Your Suunto D5 will restart to save changes. When multiple gases are activated, you can add three gases in total.
Modifying gases is for emergency cases only. For example, due to unforeseen events, you might lose a gas mixture, in which case you could adjust to the situation by deleting that gas mixture from the gas list of Suunto D5. This allows you to continue diving and get correct decompression information calculated by the dive computer.
In another case, if for some reason you run out of gas and need to use a gas mixture from a dive buddy, it is possible to adapt Suunto D5 to the situation by adding the new gas mixture to the list. Suunto D5 re-calculates decompression and shows the correct information.
This feature is not enabled by default, it must be activated and creates an additional step to the gas menu during the dive. It is only available if multiple gases are selected for the dive mode.
To enable modifying gases, turn the feature on in the settings menu under Dive settings » Parameters » Modify gases.
When enabled, during a multi-gas dive, you can add a new gas as well as select an existing gas from the gas list to remove it.
You cannot modify or remove the gas currently in use (active gas).
When Modify gases is turned on, you can remove gases which are not in use from the gas list, add new gases to the list, and modify parameters (O2, pO2) of nonactive gases.