A few of the first things that tend to come up when the sales person in your local dive shop starts talking about regulators is whether or not the regulator is balanced or maybe what its made of. And unfortunately much of the time this is where the diver is lost, their eyes glaze over and they begin the smile and nod routine being afraid to sound like they don’t know what they are talking about. Fear not! It isn’t as complicated as it sounds.
The 1st Stage
Most all regulators today come in 2 main parts or “stages”, and both can be balanced or unbalanced. To make matters worse while the end goal is the same when you balance either part, how it is accomplished and the reason for it is different for each. Let’s begin with a description of what each stage does and then break down the differences between the variations of each, starting with the 1st stage.
The 1st Stage is the part of the regulator that attaches to your tank. It is commonly made of chrome plated brass but can also be made from other materials such as titanium or with a combination of metals such as Monel, Zirconium or Stainless Steel. Titanium only serves to make the regulator lighter in weight (as well as more expensive) which can be a handy feature in your travelling luggage. Other than that, keep in mind it’s getting attached to a cylinder weighing approximately between 30 and 40 pounds. The little bit of weight you save on your regulator becomes pretty negligible at that point. Each of the various metals has a different use or function, but for the average first time regulator buyer this article is geared towards, the normal, common brass first stage is cost effective and will give years of service.
The function of the 1st Stage is to break down the high pressure air stored in your scuba cylinder to an “intermediate pressure” and send it down the various hoses for use. In most regulators this is somewhere between 130psi and 150psi and is nothing you need to ever concern yourself with unless you are certified as a regulator technician and working on equipment. With the original 2-stage regulators the 1st Stage was unbalanced. What this means to you the diver is very simple. This type of 1st Stage is reliable and dependable like that old, beat up pick up truck many of our grandfathers had. Nothing fancy or flashy, it took abuse and neglect but it started and ran every single time it was needed without fail.
With an unbalanced 1st Stage, due to basic engineering limitations and physics, the deeper the diver goes the more difficult it is for the piece of gear to do what it was designed to do. At approximately 60 feet of depth the diver will notice a drop off in performance. Breathing will become increasingly more difficult the deeper the diver uses the regulator. The diver will also notice this same occurrence with lower tank pressures as the 1st stage is designed with high pressure from your tank in mind first. The lower the tank pressure, the less force placed against the internal parts of the regulator which in turn means a lower amount of air flowing through the inner workings. None of this means this type of 1st stage is a poor choice. I’ve been to the very limits of the recreational dive planner many times using this type of regulator safely and comfortably. Examples of regulators using this type of first stage would be the Aeris A1 Regulator.
The Balanced 1st Stage compensates for lower tank pressures and deeper depths. It is designed with ease and comfort in mind to offer the diver the same breath of air from the beginning of their dive, to its most extreme depth as well as all the way to the end of the dive with a very low tank pressure remaining in your cylinder. It is equally as reliable as the unbalanced version, but does use a few more parts to perform its task.
You’ll notice that they both have several Allen Head screws or “port plugs”. These are where various necessary pieces of equipment will attach, such as your second stage or “octo”, your low pressure inflator hose for your buoyancy compensator and your gauge or computer console. Frequently you’ll have an additional low pressure port (the smaller one) that will allow a dry suit user to have an inflator hose for the bcd as well as for their suit, or possibly an additional high pressure port allowing for variations in configuring your gear. Unless you have some specialized need for a specific number of ports, this is generally not something to give a second thought to. Every scuba regulator will come with at least the necessary number of ports for the most common, basic set up of your equipment.
Other terms commonly heard when discussing a first stage would be a “piston” or a “diaphragm” design. For the average recreational diver this is nothing they need to concern themselves with. They are simply different mechanical methods of meeting the same goal in a balanced 1st stage. The differences are really only applicable to the maintenance technician in your local dive shop unless you have a specific reason to prefer one over the other.
The 2nd Stage
The 2nd stage of your regulator is the part that
a diver would keep in their mouth to breathe from. They too can be balanced or un-balanced and
offer various adjustments for the diver.
The unbalanced 2nd stage is generally light weight and has no
extra knobs or switches for the diver to deal with. The biggest advantage and selling point to
the diver is that it is commonly very reliable and has very few parts that may
need adjustment. It’s pretty simple in
thought. When it breathes poorly, it’s
time for it to be serviced. Due to their
durability and ease of servicing they are commonly found in rental departments
mated up to an unbalanced 1st stage.
The past few years the scuba industry has seen a few unbalanced 2nd
stages on the market that do offer an adjustment knob. This is a simple flow adjustment knob
designed to offer a slight adjustment in how the unit breathes. It works basically like the knob on a
spigot. Open it and more air flows,
close it and less flows. It gives the
impression of allowing the diver to fine tune their breathing but does not
compensate for depth or the diver’s position or attitude in the water during
The balanced 2nd stage has a couple purposes. First it compensates for the fact that based on simple physics the 1st stage cannot perfectly accomplish what it is designed to do. It helps give the diver an easy, consistent breath of air through out their dive. Secondly it allows the diver to “tune” the performance of the regulator to their liking often with the use of knobs and/or venturi switches. The adjustment knob seen on most balanced 2nd stages allows the diver to increase or decrease the resistance of breathing on the unit. Basically it lets it breath easier or harder to your liking. The difference between this knob’s function and the unbalanced 2nd stage’s knob is that this one will compensate for depth and surrounding pressure, keeping that consistent breath through your dive. Normally a diver will enjoy playing with this feature for a few dives, noticing the differences in resistance until they find their favorite spot and then they’ll never touch it again. The venturi switch is a simple flow restricting switch that makes the 2nd stage less sensitive to free flowing when it is not in the diver’s mouth. This is handy any time the regulator is not being used such as beach entries, floating on the surface possibly awaiting other divers entering the water or while the diver awaits their turn to exit on a boat dive and such. It is a simple “de-tune” switch that usually simply redirects air flow in a manor that makes the unit less sensitive.
Inside the second stage can be various types of vanes or items installed to direct the flow of air within the second stage. They can have various uses all designed to help with the diver’s comfort. First they aid in ease of breathing and response of the regulator by causing a swirling effect within the second stage. This vortex of air will cause the diaphragm to be sucked in with less effort, thus opening the lever within the unit that allows for the air from the hose to be delivered to the diver. Not a necessary feature, but a nice convenience for comfort. Most all 2nd stages today have something built into them to perform this. Another unintended use for these vanes comes from the manufacturers that use metal in their construction. After a few breaths the metal will begin to develop condensation on it, allowing for a few comforting drops of moisture to be inhaled. While this isn’t enough moisture to combat the dehydration that works against us, it definitely makes for a more comfortable dive often eliminating the dry scratchy through one can feel after breathing dry compressed air.
These are some the basics that the vast majority of divers
need to give thought to when selecting the correct regulator for their
uses. It mainly comes down to the level
of convenience the diver’s wishes to purchase, but rest assured. No matter what you choose you can be
comforted with the knowledge that your regulator will offer you many years of
service with some pretty basic care.