2023 232 BAR Cylinder Fills (300 bar not available)

Air | Nitrox





Gas Fills at UE

We provide 232 bar Air and Nitrox fills only from 9 am to 4.30 on days the store is open.

You don’t need to make an appointment. You can use our customer parking space in front of the building, bring your cylinders to the right of the shutters, get your fill ticket from the till and place it on your cylinders. We’ll take care of the rest.

Please ensure all kit is removed from cylinders before asking for a fill. We must check that your cylinders are tested for visual/hydro and, for nitrox, are in O2 service. There will be particular emphasis on the 5-year hydro testing, so please ensure your hydrostatic test is on a date.

If a cylinder is presented empty for a fill, our staff may refuse to fill it due to safety concerns.

Portland Dorset Air and Nitrox

Please note: Due to declining demand we no longer store Helium and have discontinued trimix fills as of December 2023.


Here at Underwater Explorers, we are serious about safety. Both yours and ours. Our two compressors are serviced annually and independently by the UK’s leading air compressor products and services provider, Motivair. Our air is tested quarterly, professionally and independently by Aquatron Breathing Air Systems, using the exact and reliable FTIR full spectrum analysis method to EN12021 which is far more accurate than Drager tubes. All fills we do qualify as Clean Air, delivered through a stacked filtering system: Air intake filters, double filters on each compressor consisting of 4 cartridges, final carbon filter. The filters are regularly replaced at 50% of the manufacturer-recommended runtime, and only hydrocarbon-free premium synthetic lubricant and O2 clean grease are used in the system.

Cylinder Fill Prices

2L 3L 7L 10L 12L 15L
Air £6 £6 £6 £8 £8 £8
28% £7 £8 £9 £11 £13 £15
32% £8 £9 £11 £13 £14 £16
36% £10 £11 £14 £17 £18 £20
40% £11 £12 £17 £19 £21 £25
50% £13 £13 £22 £26 £29
80% £18 £21 £41 £52 £62
100% £21 £26 £48 £69 £73
TWINSET – Manifolded (232 Bar)
2 x 7L 2 x 8.5L 2 x 10L 2 x 12L 2 x 15L
Air £8 £9 £13 £14 £15
28% £15 £16 £18 £22 £25
32% £16 £20 £22 £25 £30
36% £20 £25 £27 £32 £37
40% £25 £34 £36 £41 £48
ALI STAGES – 207 Bar
  40cf 7L 80cf
Air £6 £6 £8
28% £7 £8 £11
32% £9 £10 £12
36% £11 £13 £16
40% £13 £15 £18
50% £15 £20 £25
80% £26 £37 £52
100% £35 £48 £69  

1L Suit Inflation Cylinder £4

Please note, prices may be subject to change. Any change will be updated on this page.

Make the most out of your diving!

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 Our Clean Air Indoor Fill System

Our dedicated Partial Pressure filling panel provides oxygen and nitrox fills. Please ensure your cylinders are in test and in “Oxygen service” if you need any mix where pure Oxygen will be used.

We can provide air and nitrox fills to 232 bar, and pure Oxygen fills to 200 bar.

Manifolded twinsets count as single cylinders. i.e. twin 7s that are manifolded are accepted as 14L (and prices in the 10, 12 & 15L range). All cylinders are inspected for test date before filling. We reserve the right to visually inspect any empty cylinders brought in for a fill.

Underwater Explorers Gas Fills

* FTIR full spectrum analysis provides full compliance to COSHH regulations, whilst other methods fail to look for potential “hidden” contaminants.

What is FTIR air testing and how does it compare with Dräger tubes?

FTIR (Fourier Transform Infrared) air testing is a technique used to identify and measure the concentrations of various gases and vapors in the air. It works by passing a sample of air through a cell where it interacts with an infrared beam. The beam is absorbed by the sample, and the resulting spectrum is analyzed to determine the types and concentrations of gases present.

Dräger tubes, on the other hand, are a type of gas detection device that use colorimetric analysis to detect the presence and concentration of specific gases. The tube contains a reagent that changes color in the presence of the target gas, allowing the user to read the concentration from a scale on the tube.

Compared to Dräger tubes, FTIR air testing offers several advantages. Firstly, it can detect a wider range of gases and vapors, including those that are difficult to measure with colourimetric methods. Secondly, it provides more accurate and precise measurements, as it can simultaneously identify and quantify multiple gases.

Additionally, FTIR air testing is more sensitive than Dräger tubes, allowing it to detect lower concentrations of gases.

However, FTIR air testing requires more specialised equipment and expertise to operate, and it can be more expensive than Dräger tubes. It also requires a laboratory or other controlled environment to perform the analysis, while Dräger tubes can be used on-site. As such, the choice between the two methods will depend on the specific application and requirements of the user.

How is a FTIR air test carried out?

  1. Collect the air sample: Use a sampling device to collect a representative air sample from the area of interest. (In our case we run each compressor separately for 3 minutes and attach a purpose-made cylinder to the air whip, filling it for a whole 3 minutes at compressor operating temperatures ranging from 45 to 65 C.)
  2. Prepare the sample for analysis: The air sample is then extracted from the filter or sorbent tube and introduced into the FTIR instrument. The sample may be treated with a solvent or other reagent to enhance its analysis.
  3. Analyse the sample: The FTIR instrument directs an infrared beam through the sample and records the resulting spectrum of absorption, which is a unique fingerprint of the molecules present in the sample.
  4. Interpret the data: The spectrum is compared to a library of reference spectra to identify the molecules present in the sample and their concentrations. This data can then be used to determine if the air quality meets regulatory or safety standards.