Cylinder marking can vary from place to place but this one is pretty global. 

The first number denotes the month it was inspected, the second mark will be different every you see it as it is the testers stamp. The last number is the year it was tested.

Check local laws and regulations to see when scuba cylinders must be hydrostatically tested as it varies from country to country. 

Time to break out your PADI Encyclopedia of Recreational Diving!

You'll find it list the number of tissue compartments used in the design of the PADI Recreational Dive Planner, their washout times and comparisons drawn to other tables and models.


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Another question which you ca reference the constants listed at the top of every PADI physics exam. It states that every metre sea water the pressure increase is 0.1 ATM.

So the first part of the equation should be depth (35) multiplied by pressure (0.1). The answer should be in absolute pressure so we need to add the additional 1ATM that we start at from the surface. 35 x 0.1 + 1 =

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The Valsalva Maneuver has many applications and benefits when used correctly. When misused due to a prolonged or forceful application it can have several drawbacks also.

PADI always list the issue they consider primary to divers being the rupture of The Round Window but there can be more adverse effects. 

If you ever see a diver attempting forceful Valsalva address the issue and help them work on their equilisation technique or underlying issues that may be causing them to feel they need to forcefully equalise.

Interested in physiology? Why not join one of my upcoming Emergency First Response Instructor programs.

Whenever administrative questions head straight to the Paperwork and Administrative Procedures section of the Instructor Manual. 

The whole section is in alphabetical order and covers everything generally related to the PADI system.

Some more specific items may be found in the first section of a corresponding course but this should be your first port of call.

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