How to Change a Scuba Air Cylinder

Scuba diving relies upon the air supply provided by a cylinder of compressed air, sometimes simply called a scuba tank. A full diving weekend usually includes two dives and may feature as many as four cylinders, making changing a scuba air cylinder a fundamental skill taught to every diver. However, if it has been a long time between dives, a refresher on the individual steps may be needed before you suit up and get in the water again.

Things You'll Need

  • Regulator
  • Buoyancy control device
  • Air cylinders
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Instructions

    • 1

      Turn the knob on the old scuba air cylinder counterclockwise until it will not turn any further, closing the cylinder's valve. Do not tighten it any further past this point.

    • 2

      Release the remaining air in your regulator hoses by choosing either your primary or back-up second stage, or mouthpiece, and pressing the purge valve. This also double checks if the air cylinder's valve is closed. If it is still open, you will not release a single hiss of escaping air, but a continuous rush of air instead.

    • 3

      Disconnect the hose linking the air cylinder to your buoyancy control device (BCD) by pulling the locking ring back and separating it from the BCD's nipple.

    • 4

      Turn the knob on the regulator's first stage until the first stage is loose enough to remove from the air cylinder. Remove the regulator and set it aside.

    • 5

      Unclasp the strap securing the old air cylinder to your BCD, loosen the strap and pull the BCD off the cylinder.

    • 6

      Carry the BCD to the new air cylinder, slide the strap on the back over the new cylinder and tighten it. Adjust the fit so the cylinder's valve is aligned with the top of your BCD, then push the back strap's clasp down and fasten the BCD to the cylinder.

    • 7

      Set the regulator's first stage valve onto the valve of the new air cylinder. Make sure the regulator's dust cover is not in the way. Turn the first stage's knob clockwise, clamping it onto the air cylinder valve.

    • 8

      Connect the BCD hose onto the BCD's air supply nipple by pulling back the locking ring, fitting the two parts together, and then releasing the locking ring so it snaps into place.

    • 9

      Turn the gauge console away from you and any bystanders as a safety precaution and open the air cylinder's valve. Check your gauges to ensure you have a full tank of air. Also check both regulator second stages and the inflater on the BCD to ensure they are working properly.