Choosing a regulator and pressure gauge.

Training and servicing come first

How to assemble, check and breathe from a regulator, and what to do if something goes wrong, is taught by your instructor on a course. Nothing here replaces that, and we never say a regulator is safe or certified.

Servicing is for trained technicians. PADI (2015) says a regulator with an internal problem should go to a certified technician and should not be taken apart without training. DAN Europe (Guy Thomas, 2022) says makers usually require changes and servicing to be done by authorised dealers or trained technicians using approved parts and lubricants, and that non-original parts may void the CE marking and the warranty. A UK dive dealer's 2023 summary reports that many warranties depend on regular authorised servicing.

What the EN 250 markings mean

The European standard is EN 250:2014, "Respiratory equipment, Open-circuit self-contained compressed air diving apparatus, Requirements, testing and marking". Its scope sets minimum requirements for open-circuit compressed-air scuba and its sub-assemblies, aiming at a minimum level of safe operation to a maximum depth of 50 m. DAN Europe (2022) explains the markings you may see in a specification:

In other words, by DAN Europe's account a regulator carrying the ">10 C" limit is not approved for water at 10 C or colder. DAN Europe also stresses that a CE marking confirms only that minimum requirements were met; real performance still varies with design, temperature and depth.

An older maker manual frames it differently. Mares' manual for its REBEL regulator, from the EN 250:2000 era, says that edition treated water below 10 C as cold, that its regulators needed a factory cold-water kit fitted only by an authorised service centre for cold-water use, and that EN 250 equipment was not intended for more than one user breathing at once. DAN Europe's 2022 account describes the A marking as a tested two-diver approval to 30 m. The difference may come from the 2000 and 2014 editions, but our research could not confirm that, so the manual for a given regulator is the reference for it.

Our picks by category

The alternate air source

A spare second stage carried as an alternate air source has a nickname. Scuba Diving magazine, in a page we could see only as a search summary and could not confirm, says it is commonly called the "octopus", is usually yellow so it stands out, and that its performance depends on the first stage being able to supply two second stages and a BCD inflator at once. DAN Europe (2022) warns that changing or adding a second stage, octopus or hose can alter how the whole regulator performs, even when every part is CE-marked, and says makers publish lists of approved combinations.

Nitrox

A regulator for enriched air nitrox is a separate question, and agencies train divers in nitrox use, as a separate course or, at BSAC, within the Ocean Diver course; see specialty certifications. The European standard EN 13949:2003 covers open-circuit scuba for nitrox with more than 22 percent oxygen, or oxygen, and adds requirements and tests on top of EN 250. The bodies set different oxygen thresholds for treating equipment as oxygen service:

• 22 percent: the scope of EN 13949:2003.
• 23.5 percent: DAN's equipment workshop page, citing regulatory codes and safety standards, and Luxfer's requirement for its cylinders.
• 25 percent: DAN's Alert Diver (Francois Burman, 2022), at typical cylinder pressures.
• 40 percent: SDI (2012) for cylinders and valves, and the Mares REBEL manual for its regulators outside Europe only (maker statement).

DAN (2022) says only properly trained, competent technicians should perform oxygen cleaning. The maker's manual and the technician decide whether a given regulator can be used with nitrox. See nitrox equipment.

Service intervals

Each maker sets its own interval. Mares' REBEL manual (maker statement) calls for inspection at an authorised Mares service centre at least once a year and replacement of the first-stage valve every two years or every 200 diving hours. A UK dive dealer's 2023 summary reports maker recommendations: Scubapro, a full overhaul every two years, or yearly with heavy use of about 100 or more dives; Mares, inspection yearly or every 100 dives and overhaul every two years or 200 dives; Aqualung, yearly inspection and a two-year overhaul; Apeks, an overhaul at least yearly regardless of use. We could not check the dealer's figures against each maker, and the two Mares figures disagree (200 diving hours in the manual, 200 dives in the dealer summary). The interval that applies is the one in your regulator's own manual.

Care

PADI (2015) says sand can lodge in regulators and salt water corrodes metal, so gear should be rinsed in fresh water after each dive, and that hoses should be coiled loosely in storage to avoid kinks. Published advice on how to rinse a regulator conflicts, as set out on care and storage.