Newbie-Question about single gas dive settings

Hi this is my first dive computer and ı haven't dived with this yet. I will dive next week. I try to figure out how it works. Which feature it has and sometimes I change some settings to

understand. I didnt understand what is the meaning of bottom. and what is 56.3 m and this meter change when I changed oxygen percentage. thanks.

0 atj777 over 5 years ago

Bottom is your maximum operating depth (MOD) with respect to the oxygen in the gas you will be breathing.

Oxygen becomes toxic with pressure usually at around 2 atmospheres. For example, you couldn’t breathe pure oxygen at 10m.

While is is generally understood that a partial pressure (PPO2) of 2 is the critical pressure, a partial pressure of 1.4 is normally used for an added safety margin. (1.6 is sometimes used in tech diving).

So, using a PPO2 of 1.4, your maximum operating depth on air is 56.3m.

If you increase the oxygen percentage of the breathing gas, the MOD will be less. For example, 32% Nitrox had a MOD of 33m.

0 atj777 over 5 years ago

Note that you learn all about MOD in a Nitrox course.

0 9081093 over 5 years ago

atj777 thank you very much for answer