Dive cylinders are what scuba divers carry their gas in.

They are commonly made from aluminium or steel.  Composite materials can be used but then extra weight is required to be worn by the diver to allow them to sink.

Scuba cylinders are usually carried on the divers backs using a BCD, but some use a side mounted option bcd.  Some styles of diving use multiple cylinders and have Twin Tanks - two cylinders either manifolded together with an isolation valve or have them side mounted on either side of their torso.  Each tank has a valve and so the diver has two first stage regulators connected to two second stages.

We keep cylinders in stock, but do not sell online due to shipping fees and limitations.  They cannot be shipped with gas inside and so any reputable scuba filling station will want to open up an empty tank to look inside before filling.  And so they will charge you for this.

Which is right for you?

Steel cylinders have a round bottom and have to wear a boot if you want them to stand up.  They also have to be painted to stop the steel from rusting. 

In New Zealand they normally have a working pressure of around 230bar and should be paired with an equally rated valve.  The filling station can only fill to the lowest pressure out of the two, so there is no point having a 230 bar tank and a 204 bar valve on it.

Steel cylinders do not become very buoyant when the air is breathed down, so the diver generally does not need extra weight to compensate for the used air.

Aluminium cylinders have a flat bottom and so do not need a boot.  They also do not need to be painted.  Most are rated at around 204bar, but there are some higher rated cylinders.  They become buoyant from around 120bar and so the diver may need around 1kg to 2kg of extra weight when diving to compensate for lift created as the air is used.  You may notice your trim change as the air is used.

If you are trained to use Enriched Air Nitrox, Oxygen or Tri-Mix, then as you know your cylinder will need to be labelled appropriately to identify what is in it.    We like to use reusable contents labels rather than tape.

In New Zealand all scuba cylinders require a LAB or ISO number that is on the WorkSafe cylinders register to be able to be tested and filled. 

Cylinders need visually testing every year and hydrostatically tested every 2 years.

REMEMBER TO RINSE YOUR CYLINDER WITH FRESH WATER AFTER USE. THIS INCLUDES UNDER THE BOOT AND ANY NETTING. 

Salt leads to corrosion, leading to your tanks failing the annual inspection.