Regulators; Buyer's Guide

REGULATORS -  How to make the right decisions.

As the keystone of safe diving, regulators are the single piece of equipment that brings out the most questions and stirs the most debates. In this article, we will try to demystify regulators for you, allowing you to make a reasonable decision on the regulator best suited for your needs.


Basically, what we want out of a regulator is air flow - enough air under all conditions and with little effort. There are several things that cause air flow to vary. First of all, it is important that you understand that air is a fluid, very much like water. If you cause it to turn corners or change direction, it will slow down. If you make an opening too small, it will restrict the flow, especially at lower pressures. (Where you may be able to force air through a small opening at 3000 psi, it will be harder to force air through that same opening when the tank pressure is 500 psi). As we go deeper, the air becomes more dense, or thicker (Remember Boyle’s Law). This makes it harder to move the air through the same size openings. A good regulator is designed to handle these problems better than an inexpensive regulator. This is done by producing a more finely designed and machined first stage. It is the first stage where the real action takes place. There are other tricks such as large diameter hoses and devices to create venturi flows in the second stage, that will also help the flow of air. Talk to the professionals at Underwater World and they will explain these features in detail.

PISTON OR DIAPHRAGM - Balanced or Unbalanced

Ah !! The perennial debate. Usually conducted by divers who really do not understand the real difference. First of all, let us dispel a common myth. There can be balanced or unbalanced piston regulators, but a diaphragm regulator is, by definition, a balanced regulator. You cannot have an unbalanced diaphragm. Without getting into the actual mechanics of it (We do that in our Equipment Specialist Course), you should know that a good balanced regulator will maintain its breathing characteristics as you go deeper or as your tank pressure drops. In an unbalanced regulator the changes are more noticeable. Why build an unbalanced regulator? It is a simpler design and less expensive to build. It will therefore sell for less. Although an unbalanced regulator is perfectly safe to use, we generally recommend it mainly for pony bottle use only. That said, do you buy a balanced piston or a diaphragm regulator? There are some excellent regulators in both of the categories. We would recommend regulators such as the Scubapro Mk25/S600, the Aqualung Legend LX, or the Oceanic Delta 3/CDx5. Some regulators are equipped with hose swivels. Swivels on the first stage allows the regulator hose to follow the turn of your head without tugging at your second stage, which should rest comfortably in your mouth. These swivels do change the direction of air flow and they could affect the flow. "Captured" o-rings, as you find in a swivel, are usually pretty trouble free, especially if you have your regulator serviced at least once a year (Hint, Hint). And the airflow difference in a top-of-the-line regulator is negligible. Do you need swivels? No. But we do like them on our regulators.


Again, not a necessity, but nice to have. An adjustable second stage, as found on the Scubapro MK25/S600, the Aqualung Legend LX, and the Oceanic Delta regulators, allows the diver to adjust the breathing effort of their regulator, even while on the dive. It is simply a knob on the second stage that turns. Turn it one direction and it may stop a slight free flow (saving you a trip to the shop), turn it the other direction, it makes your regulator breathe easier. 


Aqualung, Scubapro, and Oceanic regulators all come with a lifetime warranty on parts. This means that you pay to get your regulator overhauled annually, and we charge any parts to them. It will definitely save you a couple of bucks. (This, of course, is ONLY available if you purchase your equipment through an authorized dealer. It is important that if you are buying equipment that you are sure. You could check the manufacturers' web site if you have and doubts). With our Preferred Customer Program, if you purchase your regulator from Underwater World you will receive a $15 discount on your annual overhaul.


Now, it is starting to come down to your preferences. The big three in regulators are Aqualung, Scubapro, and Oceanic. These are all American made and very popular regulators. This means wherever in the country (or the world) you wind up, you will be able to find parts for your regulator and people who can work on it. Buy a regulator made overseas, the parts must come from overseas. This can sometimes mean substantial delays. Stick to the home brands.


We at Underwater World believe that the best way to make a decision is to come into Underwater World and talk with our professionals. We will discuss the type of diving that you plan on doing and make a recommendation as to the best purchase for you. I tell my students that they should just find a dive shop that they trust (hopefully, that is us) and take advantage of the expertise of their personnel. There is no need for you to be a regulator expert. We can be that expert for you. Come in and see us or give us a call with any questions and we will steer you in the right direction.