■Check residual air pressure

Deep diving use a lot of air, so check residual air pressure in each of the following steps a) to e).
Also, do not use up all the air in the tank during the dive, and always leave air at least 50 bar as a reserve.

a)Before entry

Carefully check for air leaks from the equipment you set up
Apply a neutral detergent diluted with water to the connection point of the tank valve and medium pressure hose, and check for air leaks.
Also, check if there are any air leaks from the safety second and main regulators by leak sound and bubbles in water .

b)Immediately after descent

Check for air leaks from your equipment and your buddy equipment and for abnormal thing, during entry and descent.
If there is small air leak from the buddy tank valve etc., let the buddy and the team leader know and stop the dive.

No air leaks

c)During diving

Check the residual pressure gauge frequently as during deep diving air consumption is higher than usual.

Strong attention to residual air pressure

d)Before ascent

It takes 3 minutes to ascend from a depth of 30m at a 10m / min ascent rate.
Start ascending with sufficient residual pressure.

If you are using a 14-liter or 12-liter air tank, the time to start ascent is the time at that remaining air pressure is one-third.

e)After exit

Make sure the residual pressure is at least 50 atm.
If you have less than 50 atm, for your next dive, try to make the time to start ascent even faster.

Leave at least 50 atm