Scuba Tank Markings: What they Mean

How to Read Scuba Tank Markings

Written by Mario Medarevic


Whether you’re buying a used scuba tank, checking your current setup, or just curious about your gear, knowing how to decode the markings on a scuba cylinder is an important skill for every diver.

These markings tell you a lot: the tank’s specifications, service pressure, manufacturing date, and hydrostatic test history. While they may look like a string of random numbers and letters at first, once you understand what they mean, they’re actually quite straightforward.

Let’s break it down using a typical aluminum 80 cylinder as an example.


Why Tank Markings Matter

Understanding cylinder markings can help you:


Typical Tank Markings Explained

TC-3ALM-207

This tells you the tank is certified for use in Canada and constructed from aluminum alloy with a working pressure of 207 bar.


DOT-3AL-3000

This indicates the tank is also legal for use in the U.S. with a service pressure of 3000 psi.


P697426

This is the unique serial number assigned to the cylinder. It’s used for tracking the tank’s production and inspection records.


LUXFER 10A05 SO80

This gives you the exact make, model, and manufacture date of the cylinder.


11 DO/69 12

This set of markings shows the most recent hydrostatic test date.

In this example:

Tanks in Canada and the U.S. require hydrostatic testing every 5 years to remain in service.


Final Thoughts: Know Your Gear

Understanding your tank’s markings is about more than just curiosity—it’s about safety, compliance, and smart ownership. Whether you’re purchasing a used cylinder or simply doing a pre-dive check, being able to quickly decode a tank’s specs and history is an essential part of responsible diving.

If you’re unsure about any of the markings or need help evaluating a tank, visit us at Dive World. Our team can walk you through tank specs, hydro schedules, and what to watch for when shopping for cylinders.

📍 Visit our shop in Etobicoke
🌐 Learn more about tank inspections and servicing
📞 Call us for guidance on buying or maintaining your scuba cylinders

Dive safe. Dive informed. Dive World.

Questions? Call us at 416-503-3483 and speak to an experienced professional.