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Finding your VISUAL and HYDRO Test Dates

When you get a HYDRO or a VISUAL Test done on your cylinder, at Dive HQ Christchurch, we will mark your Cylinder with the date of the test.


When we do a HYDRO we stamp the date, in month/year format, into the top of the cylinder.  There may be a number of dates stamped in there, so to help make it clearer, here at Dive HQ Christchurch when we do a Hydro Test, we not only stamp the cylinder, but also give it a little paint, in the same colour that has been assigned to that year.  This year, being 2016, the colour is Baby Blue.

Here is an example on one of our new tanks, HYDRO tested in October 2015.
You can see 10  15  is the date.  That means it has had a hydro test in October 2015.  It has been painted Red = the colour for 2015.  *Note 041 is our testing station number.

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On our next example, you can see this tank has had a Hydro done in 06  15  = June 2015.  So it is also painted Red.


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Now let’s check out one from 2014.  The most recent date stamped in this cylinder is 06  14  = June 2014, and you can see it has some blue paint on it, which is the code for a hydro done in 2014. But as you can see it also has a RED tag!! This would indicate a Visual test has been carried out in 2015 (as its RED)

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VISUAL Test Dates

Around the Cylinder you will also find a plastic Tag,  this is called an ROC, (Ring of Confidence).  The colour of the ROC changes each year.

2016 Baby Blue
2015 Red
2014 Blue
2013 Maroon
2012 Black
2012 Brown

When just a VISUAL test is done, we will stamp the date on the ROC.
When the last test done was a HYDRO, you will see just an H on the tag, so you will need to look back at the date stamped on the tank for the last HYDRO test date.

On the cylinder below, we can see the blue tag around the neck, with an H on it.  This means the last test done was a HYDRO.   We can tell from the blue tag, that the last Hydro was done in 2014 (Blue Tag for 2014)


The ROC below has the date stamped on it – 10  15, which means it had a VISUAL test done in October 2015.



Please Note:-

A HYDRO is required 2 years from the latest date stamped onto the cylinder regardless of when the last Visual was carried out.

Come and see us at 103 Durham St South, Sydenham, Dive HQ Christchurch, and we’ll get your tanks tested and filled, so that you are ready to go enjoy some great diving.  We can also service your BCD and Regs for you.

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