Scuba Regulators
Purpose
A scuba regulator delivers breathable air from your high-pressure tank at a pressure that matches the ambient water pressure at any depth — making it possible to breathe comfortably at 5 metres or 40 metres. It is the most critical piece of scuba gear you own.
Features
First Stage
The first stage attaches directly to the tank valve and reduces the cylinder pressure (typically 200–300 bar) down to an intermediate pressure of roughly 8–10 bar (110–140 psi) for delivery to the second stages, BCD inflator, and drysuit hose.
- Yoke vs DIN: A DIN regulator screws directly into the tank valve. This style is more popular in Europe and with technical divers. A yoke regulator fits over the top of the tank valve and then is held in place with a tightening screw. This style is more popular in North America and the Caribbean, especially with rental tanks.
- Piston vs Diaphragm: A Piston first stages use a hollow metal piston in combination with a heavy spring to operate the high pressure valve that separates tank pressure from intermediate pressure. Diaphragm first stages use a thick rubber diaphragm with a heavy spring to operate the valve between the two chambers in the first stage.
- Balanced: A Balanced first stage maintains consistent breathing performance regardless of tank pressure — it breathes the same when your tank is at 3000psi as it does at 1000psi. An unbalanced design can feel slightly harder to breathe from as the tank empties.
- Ports: Most first stages will have 4 low pressure (LP) ports and 1-2 high pressure (HP) ports. The low pressure ports will accommodate your second stage regulators, BCD power inflator hose, and drysuit hose. The high pressure ports will accommodate your gauges and a dive computer transmitter for an air-integrated computer.
- Swivel: If the hoses are allowed to swivel (side to side when attached to the tank) this will allow for easier hose routing and a more comfortable feel in your mouth, less "tugging" feel from the regulator hose. A swivel is also common for different gear configurations, like sidemount diving. However a swivel is also considered a failure point so may not be desireable for technical diving.
Second Stage
The second stage is the part you breathe from. It reduces intermediate pressure to exactly ambient pressure, delivering air on demand with each breath. A complete regulator set includes a primary second stage and a backup second stage — the backup (called an octopus or octo) is typically a brightly coloured yellow or orange so it's easy for a buddy to locate in an emergency.pus.
- Adjustability: Many second stages include a breathing effort adjustment knob that allows you to tune inhalation resistance to your preference or to prevent free-flowing in strong currents or at the surface.
- Dive/Pre-Dive Lever: A dive/pre-dive switch also helps prevent free-flowing on the surface — the regulator still delivers air in pre-dive mode but with slightly more resistance.
- Upstream vs Downstream Valve: A downstream valve opens in the direction of airflow and is held closed by a spring. If the first stage over-pressurises, the downstream valve opens and free-flows rather than blocking air — a safer failure mode. Almost all recreational regulators use downstream valves for this reason. Upstream valves work against pressure and can potentially block under certain failure conditions.
Care & Maintenance
Regulators are an expensive investment so you should always take care when storing your regs or traveling with them. Store and carry them in a regulator bag to protect them. After each dive, rinse the regulators well with fresh, clean water. Be sure the rubber dust cover is replaced securely on the first stage prior to rinsing to ensure water does not enter the first stage and potentially damage the regulators or gauges. Prior to using them, inspect the hoses for any cracks or pin holes and check your mouthpiece for any tears or rips. Regulators should be serviced by a professional service technician according to the manufacturer's recommendation (usually about every 1-2 years or 100 dives).