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June 2009    Download the Entire Issue (PDF) Available to the Public Vol. 24, No. 6   RSS Feed for Undercurrent Issues
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Four Solid, Inexpensive Regulators

well-suited for all but the most demanding divers

from the June, 2009 issue of Undercurrent   Subscribe Now

If a diver buying a regulator in the U.S. wants to be assured that it will deliver air under extreme circumstances, he must rely on the manufacturers word. There is no independent standard, and divers have no access to independent tests. Yet in the European Union, regulators must pass certain breathing safety standards to be legally sold. A European consumer can be assured he is buying a regulator that will supply air when needed, while an American diver has to trust the manufacturer, the advertisements and the manual.

In the late 1980s, ANSTI Test Systems in the U.K. developed a machine to scientifically test regulator performance. Under hyperbaric pressure at prescribed depths, the regulator is attached to a breathing machine. The work of inhalation and exhalation is measured and a computer readout of the breathing cycle is provided. A regulator must be able to deliver air to a diver at depth having to breathe hard with low tank pressure. Some regulators fail at that. This machine also measures the drop in pressure and effectiveness of the recovery by the performance of the first stage during the breathing process. Manufacturers have widely adopted the ANSTI machine for the purpose of designing regulators to meet the criteria.

Many regulators that pass EU standards are sold in the U.S. Three of us recently tested a number of inexpensive regulators available here that pass these ANSTI tests. George Brown, a working diver in the Scottish Highlands, is a BSAC National Instructor. Colin MacAndrias is a PADI Master Instructor. I have instructor certifications with both those agencies. Going off the beach at the Aqua-Sport International diving center at the Taba Hilton in Egypt, we took the regulators diving in a side-by-side comparison to see the differences.

A European diver is assured by the
European Union he’s buying a
regulator that will supply air when
needed, while an American diver has to
trust the manufacturer.

We tried to beat the regulators by breathing as hard as we could. We inverted them to replicate a panicking diver who might stuff someone elses regulator in his mouth upside-down. (Inevitably, small amounts of water will enter when the port opens to release exhaled air. The question is whether this water has somewhere to drain or whether it interferes with breathing.) We checked how easy it was to activate the purge valve, and whether there was a tendency to free-flow uncontrollably when a second stage was dropped from the mouth. We considered the overall breathing experience. We got to know how each stacked up against the others. The tests were briefly interrupted at times: A giant green, free-swimming frogfish decided to perch on my head.

As a rule of thumb, piston-type regulators tend to give bigger gas flows and a faster response, while diaphragmtype regulators are less inclined to develop operating faults in very cold conditions. Many had only one high-pressure port, which might make you disinclined to employ a gasintegrated computer with it. Some had knobs that allow you to increase the amount of effort needed to draw open the demand valve. Some had Venturi controls that enable you to reduce the chance of an exponential free-flow at the surface that is caused by cleanly flowing air passing the back of the pressure-sensing diaphragm of the second stage. A couple were designed for trouble-free use in very cold freshwater.

Apeks ATX40 DS4 (list price: $595; www.aqualung.com) One of the few diaphragm-type regulators we tested (and coldwater rated), it has a dry-sealed first stage with four mediumpressure ports conveniently positioned. The one high-pressure port was positioned well away from the others so that there was room to fit a computer transmitter. The second stage has a Venturi control.

GB: It proved a good breather and very comfortable. It gave lots of gas on demand but when inverted, it was almost unusable because it was so wet. I cant believe the price!

JB: The air came in a broad flow into my mouth. I couldnt beat it no matter how hard I breathed it. Inverted, it was damp the first time I tried it, but I managed to still use it; if it freeflowed first, then it was almost totally dry. I felt it was always on the edge of free-flowing and when it did, the flow of gas was massive. The Venturi switch should be set to minus before you take it out of your mouth at any depth.

CM: It seemed to be very efficient at delivering air no matter how deeply I breathed. The purge button gave a very soft blow of air. Its very sensitive to demand but you pay for that because it tends to free-flow immediately if you take it out of your mouth.

AquaLung Calypso ($275; www.aqualung.com) This regulator has a simple piston-type first stage with a single high-pressure port and four medium-pressure ports arranged around its barrel so that hoses fanned out around it. The second stage has a Venturi control.

GB: This is an excellent regulator. When really breathing heavily, I detected a fine mist of water, yet when inverted it was perfectly dry.

JB: A pleasant breathing experience; there was a voluble flow of gas that diffused nicely in the mouth. The purge was strong but the flow of air was equally diffuse too. It was perfectly dry while breathing from it inverted.

CM: There was very little resistance to inhalation. It gave a crisp breathe every time. There was never any sign of a freeflow. Inverted, it gave a minute spray of water. The purge was very effective but not a tonsil blaster.

Cressi Ellipse Black MC5 ($309; www.cressisubusa.com) A compact diaphragm-type first stage and an oval shaped second stage distinguish this regulator. There are a single high-pressure port and only three medium-pressure ports but well-spaced for a good hose routes. The neat second stage has a narrow exhaust-T that could lead to exhaust bubbles interfering with vision. It has a Venturi control.

GB: Very good, if delicately tuned. It would easily free-flow when dropped out of my mouth. The purge was easily controlled and proved reasonably dry once fully inverted.

JB: It delivered more than enough air but in a narrow cone. I felt that it was quite a damp breath when the regulator was sideways with the hose side downwards, but once fully inverted, it was reasonably dry. The purge took a hard push to activate and the effect was not very strong.

CM: Air delivery was good but it hissed a bit with deep inhalations. Inverted, it became wet. The purge was very weak.

Mares Rover 12 ($300; www.mares.com) This new regulator has a diaphragm-type first stage with an overly large barrel that affords good spacing for the two high-pressure and four medium-pressure ports. It has a marked port for the primary second-stage hose. The second stage had no visible metal parts but it included the bypass tube that obviates the need for a Venturi control.

GB: I got a comfortable and uniform supply of air across the whole breathing cycle even when I worked hard. When inverted, only a slight mist of water was detectable. The purge was extremely effective.

JB: There were masses of breathing gas available. It was an eye-opener in comparison to other regulators I still thought were good. The purge control was a little hard to push but the purge was very effective. Inverted, it was a little damp but eminently usable.

CM: An excellent regulator that gave gas with little effort. There was no splash whatsoever when inverted. The purge needed a heavy press but once done it had a powerful effect.

Oceanic Alpha8 SP5 ($350; www.oceanicworldwide.com) This regulator has a piston-type first stage, with one high-pressure and four medium-pressure ports arranged around its narrow barrel. The last medium-pressure hose fitted always ended up in an awkward spot. The neat-looking second stage has no knobs and the mechanism is easily accessed for removal of grit.

GB: This regulator performed perfectly. It gave an excellent breathe from the surface all the way to 120 feet with an even supply of gas at all times. There were loads of air and no effort. Inverted, it was quite useful despite a fine spray of water.

JB: It answered the call when I really tried to beat it by heaving on it hard. It was not too wet for comfort when inverted and the purge was easy and effective.

CM: It gave a very good breathing rate with each inhalation very crisp. It was good at all angles and even when inverted it was wet but very manageable. The purge gave a sharp full thrust of air.

Scubapro MK2 Plus/R295 ($285; www.scubapro.com) A piston-type first stage with water-flow holes big enough for quick response. It has four medium-pressure ports arranged close together and a single high-pressure port spaced apart from them. The nice second stage has no knobs.

GB: I gave this full marks in all categories except when inverted, when I detected a fine spray of water.

JB: It gave a slightly tighter breathe than some of the better regulators. It also gave a lower frequency sound, probably indicating the air path was broader. At depth, when I really breathed hard, it seemed a bit asthmatic, and it squawked at times. The purge was very progressive, which was nice, but when it was inverted, I choked on a fine spray of water.

CM: This was a very effective regulator with a delivery of gas that was nicely diffused in the mouth. I felt no spray of water when it was inverted and the purge control gave a full effective blast.

Conclusion: Although each of us had our own favorites, none really stood out above the others. Wed be happy to use any on future dives. If pushed, wed single out, in no particular order, the Oceanic, the Mares and the Apeks (though it is almost twice the price of the others) as slightly more satisfying in performance than the AquaLung, Cressi and Scubapro.

John Bantin is the technical editor of DIVER magazine in the United Kingdom. For 20 years, he has used and received virtually every piece of equipment available in the U.S. and the U.K., and makes around 300 divers per year for that purpose.

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