Whether you are looking for a budget breather for a new diver or a high performance blaster to take you to the edge of the twilight zone you’ll find what you are looking for in one of these five new regulators. These regs range in price from under $300 to just under $600. While these are the new kids on the block they aren’t the only ones from which to choose. Check out our Best Scuba Regulators article to see those previously reviewed.
Recommended Scuba Regulators by RDC’s Experts
Each of the following regulators can get you underwater but features and performance are directly related to price. Just like taking a drive in a two door compact or a luxury SUV. They both get you where you are going but the style, comfort and speed will be much different. The benefit here is that you don’t have to spend a fortune to get a perfectly functional regulator. However if you are going to be diving the boundaries of the recreational limit or just like having all the bells and whistles you should expect to invest more in your reg.
We started our Reg tests at Dive Lab, in Panama City Beach, Florida, home to the only independently owned and operated state-of-the-art ANSTI Breathing Simulator in the country. Dive Lab’s director, Mike Ward, made time in his busy schedule to run our rigorous test protocol that he developed to get down to brass tacks and see how these regulators really stand up under pressure.
Each reg was attached to the ANSTI breathing simulator and taken through our Breathing Simulator Test Protocol. Tests captured hundreds of data points and 50 pages of Breathing “Loops,” a graphic representation of a regulator’s breathing performance. These test results created a laboratory picture of how these regs will perform at recreational diving depths as well as when pushed to extremes. (See Breathing Simulator Test Results Chart.)
Lab tests completed, it was back to Southern California where we summoned the RDC test team and hit the water to collect some real-world diving data. Six experienced test divers, armed with RDC’s ocean ergo test protocol printed on waterproof paper and attached to underwater slates, evaluated each reg over the course of two days of diving, all of which went into the individual reviews that follow in alphabetical order.
Aeris AT600 Ion LT
The AT600 First Stage and ION LT Second Stage is the latest version of the flagship AERIS ION Regulator specifically designed for the traveling diver. The AT 600 first stage is very light and compact, weighing just 1.5-pounds. The reg comes nitrox ready up to 40-percent and offers an optional dry environmental kit.
The ION LT second stage is compact and has dropped some weight by replacing the swivel and standard hose with a lighter MaxFlex braided hose. The pneumatically balanced second stage has a flow control knob and venturi lever for breathing adjustments, and an orthodontic mouthpiece for comfort.
The AT600/ION LT feels as light as it looks. The Dynamic Adjustment control knob has a range of 2.5 revolutions that takes it from nearly effortless breathing to a hard draw. Somewhere in between you should be able to find what is comfortable for you. The venturi control lever is small in size but easy to find above the flow control knob. While the lever is not marked the function is intuitive as the lever is down for dive and up for surface. Hose set up is slightly limited by the port configuration. The left side of the first stage has the HP port for your pressure gauge and one LP port for an inflator hose. If you also want to run a drysuit inflator hose you will need to tap into one of the LP ports on the right side or flip the first stage upside-down and run your HP hose off the right instead of the traditional left side.
On the surface the venturi wasn’t always able to prevented freeflow. This was the case with almost all of the higher performance regulators. Underwater the regulator breathed nice and smooth. The breathing adjustment knob provided a very noticeable and wide range of flow. We preferred the adjustment set wide open. The mouthpiece was soft, comfortable, and secure with high-density bite tabs. The ION LT second stage was very dry in both the swimming and head-down positions. Bubble interference was zero while swimming due to the swept-back exhaust tee. Clearing the second stage required minimal breath due to its low volume and the large purge button was powerful. The new MaxFlex hose offered a comfortable range of motion with little pull at the mouth. The AT600/ION LT is so new that we received our test unit after the ANSTI testing date. The warranty is comprehensive and offers a lifetime of free replacement parts if the regulator is serviced annually.
We really liked the compact size of both the first and second stages. We were impressed with the ease and dryness of breathing and the exhaust design that kept bubbles out of our view. As a travel reg the AT600/ION LT delivers as promised.
Aqua Lung Legend LX
The “Legend” continues but the new Legend LX is smaller and lighter than the original.
The first stage has a slightly different look but some changes are internal and less noticeable. The medium pressure chamber has been enlarged to provide all ports with equal access. The first stage is environmentally sealed to keep water out of the spring chamber and the Auto-Closure Device (ACD) keeps water out of the first stage inlet to prevent corrosion.
The second stage is where most of the visible changes are found. It has a smaller profile and lighter feel with a new AquaFlex hose. The biggest change however is the Master Breathing System (MBS) a dual-function breathing control knob that adjusts both airflow and venturi position. It not only makes going from Pre-Dive to Dive much easier and quicker, it gives the case a cleaner look. It comes with a Comfo-bite and standard mouthpiece to suit your preference. The new Legend LX is Nitrox ready up to 40-percent O2 and comes with a warranty that includes parts for life if you follow the annual service requisite.
The dual control Master Breathing System was the only venturi system in this group of regs that consistently prevented a freeflow at the surface. This may be partially due to the purge cover design that restricts travel of the diaphragm. No matter how many times we dropped the second stage into the water with the purge hitting the surface first it would not freeflow. Once underwater we turned the adjustment knob open for some dry and easy breathing. The second stage felt light in the mouth with the new flex hose and angled ports directing the hoses forward. The exhaust tee is compact and stays within the slipstream of the cover but stretches back to let bubbles escape behind and out of view. Clearing is easy and comfortable with the travel of the purge button reduced preventing too much of a good thing. ANSTI breathing machine tests confirmed our suspicions that the legendary performance would also be carried forward. The Legend LX scored excellent in our four standard breathing tests and barely slowed down when we pushed it beyond the extreme.
The Legend LX is the top of the line. Aqua Lung also offers the Legend LUX that features a Gold/Pink finish for a few bucks more but it’s the classic chrome finish for us.
Cressi MC5 XS Compact
The new MC5/XS Compact is only half new. The MC5 first stage is already a workhorse in the Cressi line. This pairing puts the new XS Compact second stage with a proven performer for a regulator that is sized cressi mc5gright for travel. The MC5 first stage is a compact first stage but slightly limited with hose routing since it has only 1-HP port and 3-LP ports. While it is not usually an issue for warm water travel if you want to dive a drysuit you might not have enough LP ports. That aside the MC5 is perfect for its intended purpose, an inexpensive travel reg. Under water the polymer second stage was light and comfortable. The front cover purge is large, cleared water efficiently and was generally a dry breather. The exhaust tee is hidden within the outline of the reg but bubbles are noticeable when not looking down. The mouthpiece is soft and was a comfortable fit. The top mounted venturi control was easy to operate but like most others in this review it didn’t always prevent a freeflow when dropped face first into the water. In the Dive position the venturi was effective and increased ease of breathing at depth. The MC5/XS Compact is so new that we received our test unit after the ANSTI testing date and the retail price has yet to be determined.
Cressi states that the MC5/XS Compact is designed to be an inexpensive regulator suitable for beginners and rental departments and travel. With that in mind we would put this reg at the top of that category.
Oceanic Alpha 9
The Alpha 9 is a budget regulator. It’s the lowest cost reg in this report and while it lacks many features found in other regulators that sell for more than twice the price it has what’s most important, respectable performance. Surprisingly it does sport some comfort features like a MaxFlex hose and orthodontic mouthpiece. It’s Nitrox friendly up to 40-percent and comes with a warranty that includes parts with Oceanic’s Alliance Service Agreement if you maintain the annual service schedule. Not only will your initial cost be low, so will your upkeep.
The Alpha 9 second stage married to the SP-5 first stage is designed as an entry-level regulator. It rated Very Good at depths and breathing rates that most closely represent the sport diving limits in our ANSTI breathing machine tests. On test dives the ease of breathing scored high in the normal swimming position. We were surprised how well it kept up with regulators out of its league. The Alpha 9 was a very dry breather and its large front cover purge was strong and quick to clear the case. The mouthpiece was very comfortable and the flex hose kept strain at the mouth minimal. While the regulator lacks external adjustments the air delivery was smooth with a roller lever to reduce effort, which is usually found only in more expensive regulators.
The Alpha 9 is indeed a budget regulator but lucky for you Oceanic designed it to meet the U.S. Navy’s Class A standards, which means you get performance too.
The Tusa RS-790 is a feature rich reg without the high price tag. It has a balanced diaphragm first stage that’s environmentally sealed and sports a ribbed section to resist freezing in cold conditions. It also has two dedicated LP ports that offer 15-percent greater airflow, a benefit when diving deep where air is denser. The second stage is pneumatically balanced and offers an adjustable venturi for easy breathing at depth or working hard. The case is made of a lightweight composite and comes with an ergonomic mouthpiece. The RS-790 comes with a lifetime warranty including free parts for life when serviced annually.
We found the RS-790 to be a great all-around performer without being finicky. While it doesn’t have a flow adjustment knob, it’s pneumatically balanced which sets the ease of breathing very high. The venturi adjustment was effective at depth but like other high performance regs didn’t always prevent free-flow at the surface when belly flopped into the drink. The front cover purge was pliable and cleared quickly. Bubble dispersion was excellent while on the move but crept into view when stationary. The regulator felt light and breathed dry in all positions. The medium sized mouthpiece was a good fit for all the test divers. On the ANSTI machine the RS-790 scored Very Good all the way to 198’. Giving more than most divers will ever need.
If you want one of the best performing regulators that you’ve never heard of, the Tusa RS-790 gives you a lot for your investment.
Regulators Breathing Simulator Results
|Legend LX||Tusa RS790||Aeris AT600/Ion LT||Cressi MC5/XS C||Oceanic Alpha 9/SP5|
|37.5 RMV @ 132’||5||5||*||*||4|
|75 RMV @ 132’||5||5||*||*||3|
|62.5 RMV @ 165’||5||5||*||*||3|
|62.5 RMV @ 198’||5||5||*||*||3|
|75 RMV @ 198’||4||4||*||*||**155’|
*We received these regulators after the ANSTI testing date.
**While not able to reach the established depth for this RMV/depth test level, this is the actual depth the regulator was able to attain before exceeding test parameters.
Simulator Chart Scoring
There is no better way to determine a regulator’s raw breathing performance than to strap it to a breathing simulator. The total effect of a reg’s gas-flowing abilities is the result of a combination of its inhalation and exhalation effort, known as Work of Breathing (WOB) and represented in joules per liter (j/l). We’ve taken each reg’s actual WOB for each test level and converted it into a scores to make it easier to compare performance from reg to reg.
5 = EXCELLENT
Any regulator able to achieve the applicable RMV/depth test level with a Work of Breathing less than 1.00 joule per liter (j/l).
4 = VERY GOOD
Any regulator that can achieve the applicable RMV/depth test level with a Work of Breathing of 1.00 j/l to 1.50 j/l.
3 = GOOD
Any regulator able to achieve the applicable RMV/depth test level with a Work of Breathing of 1.51 j/l to 2.25 j/l .
2 = FAIR
Any regulator able to achieve the applicable RMV/depth test level with a Work of Breathing of 2.26 to 3.0 JL (the European conformance standard EN 250 limit).
RDC’s Breathing Simulator Test Protocol Explained
In keeping with Dive Lab’s rigid protocols, regulators are placed in a pressurized wet tank and tested at a combination of three RMVs (Respiratory Minute Volumes), or breathing rates, at three test depths. Breathing activity is tracked on a computer screen, which represents each reg’s performance in the form of a “breathing loop,” which takes all the data points at each test level and translates it into a graphic presentation of a regulator’s work of breathing or WOB, which averages four complete inhalation and exhalation cycles into one graphic image.
• Tests are performed at a supply pressure of 725-775 psi. This obviously is a very low supply pressure and helps to identify a reg’s strengths or weaknesses (tests have shown that virtually any reg will perform admirably at shallow depths with a supply pressure of 3,000 psi. Only by pushing the envelope can you see the differences in performance between regs.
• Just because a reg fails to achieve a test level doesn’t mean it shut down or failed to deliver gas, only that if wasn’t able to deliver that gas within the strict guidelines of respiratory rate, depth and supply pressure with the parameters of the tests.
• Although RDC tests regs at nine different depth/RMV test levels for a complete picture of a reg’s behavior at depth, to avoid burying the topic in too much data, we focus on five fundamental test levels, each representing specific parameters that can either be connected to real-world diving conditions, or that adhere to current industry testing parameters for purposes of comparison.
• Following are the five test levels RDC focuses on, with explanations on how they might relate to your personal diving experience. These explanations can also be applied to the Simulator Test Results Chart.
TEST LEVEL #1:
37.5 RMV @ 132’ FSW:
The respiratory rate of 37.5 RMV is close to what a fit recreational dive taking slow deep breaths would do when finning a long distance. A diver could theoretically maintain this rate for about five minutes without becoming significantly winded. The 132-foot depth is the maximum depth recommended for recreational diving. According to Dive Lab, this test level also provides a good view of the smoothness or lack of smoothness of the demand valve without significantly taxing the flow capability of most modern regulators. Finally, it helps show a consistency curve when compared to higher RMVs.
TEST LEVEL #2:
75 RMV @ 132’ FSW:
The respiratory rate of 75 RMV is considered an extremely heavy work rate and cannot usually be maintained by even a very fit person for more than a couple minutes. This work rate is used to show the regulator’s reserve potential, and can also be used to simulate two divers buddy breathing off the same reg.
TEST LEVEL #3:
62.5 RMV @ 165’ FSW:
The respiratory rate of 62.5 RMV is generally accepted as a “heavy to extremely heavy” work rate. A very fit working diver could not generally maintain this rate for greater than three to five minutes. 62.5 RMV is also the standard high work rate used by the US Navy and it is the European conformance standard EN250 for evaluating regulator performance. Consequently, this is the test level most often referred to by reg manufacturer when R&Ding and marketing their regs.
TEST LEVEL #4:
62.5 RMV @ 198’ FSW:
The respiratory rate of 62.5 RMV at a depth of 198 feet is what the U.S Navy uses for its Class A reg testing, although the Navy uses a higher supply pressure. The combination of breathing rate and depth provides a good stress point for a regulator for identifying reserve capacity.
TEST LEVEL #5:
75 RMV at 198′ FSW:
This is more of an extra-credit sort of deal. If a reg can reach Test Level #4 without exceeding test parameters, an impressive feat in its own right, just out of curiosity we hit the switch and increase the breathing rate to 75 RMV just to see what happens. If the reg can’t take the breathing rate at the 198-foot depth, we back off to find the deepest depth the reg can handle at this breathing rate, and mark that on the performance chart.
I’ve been a diving addict since my 14th birthday when my parents took me to the Bahamas and had my first scuba diving experience. I’ve been an active diver ever since but in the last few years my focus shifted on sharing my thoughts and experience on diving gear, writing product reviews and gave up on organizing dive tours.