How do I know that my cylinder and valve are Nitrox Ready?
Once a cylinder and valve have been prepared for nitrox service, a special sticker (or often a special version of the evidence of visual inspection sticker) is affixed to the cylinder. Unless the sticker explicitly states that a cylinder and valve are suitable for nitrox service, they are not. If the cylinder is ever filled with anything other than Oxygen-Compatible breathing gases, it is no longer suitable for nitrox service, and the sticker should be removed. Even with the best quality fills, hydrocarbon contamination can build up over time. Fill Express recommends that the cylinder and valve should be prepared for nitrox service each time the cylinder is hydrostatically tested.