In Australia all SCUBA cylinders are required to be hydrostatically tested every twelve months


In Australia, all SCUBA cylinders are required to be hydrostatically tested every twelve months. This must be carried out in accordance with Australian Standard AS2337 and AS2030.1, it can only be done by an accredited Test Station. Ozaquatec Scuba Service Centre is an accredited SAI Global Test Station – No: 723. Your cylinder is stamped around the neck area indicating the month and year it was tested along with the test station number.


If your scuba cylinder is out of test it will not be filled by any scuba shop. Just as important as having your tank hydro tested is having your valve serviced. Valves don’t require a yearly test unless you are frequently diving (approx. 100 dives per year), but you should have it serviced every 2 years at least.


NOTE: Under our SAI Global accreditation the following cylinders will no longer be tested and their design approvals have been withdrawn effective 31 October 2017 – All aluminium alloy 6351 cylinders. View PDF



The cylinder is drained of air and the details of your cylinder are recorded on a test report including owner’s details, serial number, manufacturer, cylinders specifications, standard to which it is manufactured and the test pressure. A visual inspection is then carried out looking for damage including dents and corrosion that may affect the integrity of your cylinder and this can lead to it failing the test. The valve is removed and if in the opinion of the technician the valve requires to be serviced it will be and usually is at an additional cost.

Cylinder valves not fitted with the correct burst disk assembly will undergo a valve service and correction, this also is an additional cost. The neck threads and internal area of the cylinder are checked for pitting, rust, wear and corrosion. Often older cylinders particularly aluminium often fail in this area as the neck threads is often worn beyond the allowed tolerance. This is an automatic failure under the testing standards. Cylinders can be subject to internal rust or corrosion due to moisture. This is commonly due to poor filling procedures and poor air quality.

NOTE: You should always check that the fill station has an in-date Air Quality Test Certificate and this must be displayed. It is your responsibility and in your best interest to check this. Rust or internal corrosion of your cylinder does not mean it cannot be repaired. The cylinder can be brushed using specialised brushes a process commonly known as whipping. Another method commonly used method is that of rumbling. This is the process by which terracotta balls and/or other mediums are used to facility the cleaning process. Wood chips can also be used to help remove dust and rust particles prior to further inspection, testing and cleaning. This process can be time consuming but is effective.

If your cylinder passes the above inspections, it is then ready to be hydrostatically tested. It is filled with water and connected to the test panel. The cylinder is pressurised to its fill pressure, it is checked for leaks and air bubbles and for the panels’ accuracy before the main test is carried out. Once this is complete the cylinder is then pressurised to its test pressure and held there for no less than 30 seconds. The pressure is slowly released, and the level is recorded. The cylinder is then disconnected from the test panel and drained. It is then inverted and placed on warm air driers to ensure it completely dries.

One final internal inspection is carried out and then the neck O-ring is replaced, and the valve reinstalled. The cylinder is stamped in accordance with Australian Standards, filled, leak tested, the report completed and signed off by a signatory. Any cylinders that fail this test are subject to be stamped failed (FAILED 723) in accordance with the Australian Standards.

The cost is minimal for such a timely process. Our price includes your air fill and O-ring @ $57.00 per cylinder. Our normal lead time is 1 to 2 working days for tanks to be hydrostatically tested. Please check with our staff for conditions of same day turnaround. If you require any further information on SCUBA cylinder testing or have any queries please feel free to contact us.

Helpful Hints:

  1. Never buy a second-hand cylinder without seeking good advice first.
  2. Your valve may not be serviced unless you ask for it or if it is damaged, in poor condition and noticed by the technician.
  3. Your cylinder test stamp has the month and year, so it is due by the end of the month it is stamped at.
  4. Ensure whoever is filling your cylinder has an air quality test certificate and it is in date.