I REMEMBER BUYING MY FIRST REGULATOR. I was surprised to find how expensive these items were, but I wanted one that would give me all the air I needed when I required it.
    The shop assistant asked me how deep I intended going. As a new diver, I thought 30m would be deep enough, thank you. He sold me a little Spiro regulator with a tiny unbalanced-piston first stage and a metal second stage with all the design finesse of a tin of boot polish. I learnt to dive with it.
    The Spiro regulator was unusual in that it put the medium-pressure hose over your left shoulder. This proved invaluable when I graduated to more serious diving and started routinely to use two tanks on my back. I bought another regulator, a right-handed top-of-the-line model, and went on to dive to depths that are now inconceivable using air.
    Around this time, one Mike Todd caused a furore by taking all the regulators he could lay hands on and testing them with the newly developed ANSTI breathing machine. He found a great number of them unsuitable for taking to 50m and some incapable even of performing satisfactorily beyond 18m. Always at the forefront of diving developments, Diver reported his findings.
    The funny thing is that I was never disappointed by the air supply from that little tin of boot-polish at the time.
    Shortly after this, the BSAC adopted the use of octopus rigs in preference to buddy-breathing and set about trying to formulate a technique for tandem-breathing, to avoid over-demand on a valve mechanism by two divers using it at once.
    Diver now caused another uproar. We went under water and proved that a valve equipped with four second stages could more than adequately supply air to as many as four divers simultaneously at 55m. We tried eight different makes, and although some were better at it than others, they all worked. However, certain manufacturers were upset that we had not chosen their product as the best, and protested by withdrawing their advertising.
    People are people and machines are machines. Both have their place when it comes to differentiating between the breathe given by a scuba regulator.
    The next time we tested regulators, we combined deepwater tests with real divers with the cold, hard results of the ANSTI machine. And so started the tradition of regular comparison tests of regulators in these pages.
    The last time we tested regulators, we asked manufacturers to send us one or two examples of their wares. They tended to send the best they had plus one other.
    But how well, we wanted to know, would their really cheap regulators do? How well would we get on with the modern equivalent of that little tin of boot polish?
    This time we asked manufacturers (or their distributors) to send us an example of a regulator with a recommended retail price of less than £150. This approach brought one complaint from a manufacturer which had nothing to offer at this price. What was it worried about?
    Most of the regulators supplied came with unbalanced-piston first stages. This means that the work of breathing tends to increase as tank pressure drops below 50 bar. However, it is our view that no diver should be at great depth when his air supply is so depleted, and the effect is hardly noticeable in the shallows.
    None of the regulators tested in this group are personally recommended by us for use in cold fresh water, as most have no specific coldwater design features. However, a number of the manufacturers claim that their regulators do meet EN250/2000 coldwater standards.
    We went to the Coral Hilton, Nuweiba, in Egypt to do the testing. The Sinai's Red Sea in January gave us calm, deep water close to the shore, with negligible tide, and it is cheap and easy to reach. We managed a series of two dives deeper than 40m each day during a one-week trip.
    Had we tried doing this in Britain, we would still be waiting for the right weather and sea conditions, and the divers would have had trouble recalling how each regulator compared during the inevitable intervals.
    Each test diver carried two tanks, thanks to the Buddy Tech-Wing and Trident BCs lent to us by AP Valves for the project. Buddy twinning-bands and blocks enabled us easily to twin up the aluminium cylinders supplied to us each day by Emperor Divers, the local operator based at the Coral Hilton.
    Emperor also kindly supplied one of our test divers and all the shore back-up we needed, including the use of a Jeep and trailer to get to where we needed to go.
    Two tanks per diver meant that each could directly compare two regulators throughout each dive. At the same time these regulators were equipped with alternative second-stages (octopus rigs) so that at depth each diver could try the two regulators of a buddy, both in a tandem breathing situation and alone. In this way, every test diver got to try and compare every regulator.
    Regulators were also compared in different head positions, as well as inverted. We felt the inverted position was important, because in the frantic moments of a real out-of-air situation, a panicked diver might put a regulator into his or her mouth upside-down.
    All gave a wet breathe, but some were wetter than others. However, if you took time to purge an inverted regulator well, it was usually dry enough to breathe from.
    For each dive we swam out from the shore about 300m to the same spot, marked by an old submerged ship's mooring dating from the Israeli occupation of the Sinai. We dropped down to 43m. The swim back up the reef afterwards gave us both time to decompress and make additional comparisons. The dives lasted between 45 and 50 minutes depending on the decompression time required. We used the requirements of the Suunto Vyper as our decompression guide.
    My job was to select a group of divers who were both non-partisan to any particular brand and experienced enough to carry out the project without hitches. I acted as underwater monitor, there to anticipate any problems such as "lost" second stages or tangled hoses, so that valuable time at depth was not wasted.
    I was careful not to ask leading questions in my post-dive debriefings, and wanted to be satisfied that the comparisons were as fair and uncompromised as possible. I asked each test diver for their favourite of the day. Gradually, over the week, it became apparent that one regulator was clearly the best.

ANSTI testing
We returned to the UK and sent all the units off to ANSTI Test Systems for that company's independent findings with its breathing machine. By this time the regulators were no longer the shiny new examples that had been sent to us, but we were interested to find out how well the machine's results corresponded with those of our human testers.
    Each regulator was tested on the ANSTI machine to European Standard EN250: 2000 in the same way that we would have tested any model, regardless of retail price. Water temperature was 10.6°C and air supply pressure (tank) 55 bar. The ventilation rate was 62 to 63 breaths per minute with a tidal (lung) volume of 2.5 litres at 25 breaths per minute.
    The ANSTI pressure-volume diagrams shown on the following pages represent one complete breath at maximum depth, normally around the 51m mark, with the exhalation in the red area above the line and the inhalation in the blue area completing the cycle. The perfect profile would be a nice, smooth oval shape.
    Results given by the machine were for the most part uncannily in line with the findings of our test team.

Conclusion
We were agreeably surprised to find that nearly all the regulators tested were capable of giving the air needed by two divers at one time at 40m-plus. However, as the week progressed it became apparent that certain regulators were favourites.
    Among these were the Mares MR2 Axis and the Dacor Fury, the Scubapro MK2/R190, the Aqua-Lung Calypso and the Ocean Reef Enterprise.
    As time went by, however, it became clear that one regulator stood out from the others. When it came to a leisure dive on the last day, with a single tank and regulator, everyone wanted to use the £143 Oceanic Alpha 7.

Kitting up at the Emperor dive centre. Each diver took two regulators on each dive


tandem-breathing at 43m


noting down the conclusions


checking out the regulators on a deco stop


Still comparing experiences - from left, Les Holliday, Leen Charle, George Buxton and Steve Weinman

GEORGE BUXTON, with 23 years' diving experience behind him, is a veteran of Diver's regulator tests and was one of those divers who originally proved that one regulator could supply four big divers at 55m. He has been on the test-team once more since then. He runs a very successful business as an electrical contractor and is also proprietor of the Herts and Essex School of Diving.
LES HOLLIDAY, a founder-member of York BSAC, is a marine biologist. He is well known as a marine consultant and is a busy author and journalist for the aquarist press. He has more than 40 years of diving experience and has been involved in five Operation Raleigh expeditions and won two Prince's Trust awards. He is a part-owner of mv Indian Ocean Explorer.
LEEN CHARLE, born in Bruges, Belgium, works with her husband Jan Christiaens running Emperor Divers' Nuweiba dive centre. She has nine years'experience of working as a diving instructor in the Maldives, the Cayman Islands and Egypt. Like all divers working on-site, she isinterested in which gear gives the required results rather than dogma.
STEVE WEINMAN is Managing Editor of Diver. With eight years' diving experience behind him, this is the second in-water regulator comparison test in which he has participated. He is foremost a journalist and follows the publish-and-be-damned school of thinking. I was confident that he would publish our findings, however controversial the results!