A GREENGROCER HAS A SACK OF POTATOES. He puts half in one hopper marked up at 90p a kilo and the other half in a second hopper marked up at £1.90 a kilo. This way he pleases two sets of customers.
     People on a budget would like to have the best potatoes but have to content themselves with the cheaper ones offered. Those who want the best and are prepared to pay for it feel they are getting their money's worth. The potatoes are actually the same but, hey, that's marketing! It's a familiar scene at any retail outlet. Quality is often demonstrated by the price charged.
     The big question is, do you really get what you pay for?
     Regulators have been getting more expensive but it does not necessarily follow that they give better performance. However, when it comes to intangibles people are prepared to pay a lot, especially if it is for something as important as breathing.
     In recent times we have compared regulators in the budget price range up to £150, and also those with retail prices between £150 and £300, and have discovered some pretty good ones.
     Now we compare regulators without price restriction. We select those that purport to be the best - at any price.
     We asked manufacturers and distributors to send us their best regulators that retailed for £300 or more. Our first surprise was that the range of regulators submitted was not as expensive as we had expected.
     We are pleased to say that most of the regulators tested in this price range performed well. We were expecting that. During testing it became clear, however, that some performed better than others.
     Times change. The Swedish company Poseidon has always been famous for regulators capable of generous air delivery and its products used always to be among the most expensive. Not any more. On the other hand, Apeks, once the Cinderella British manufacturer that made breathing-valves few wanted, has turned its business around with high-performance products that command top prices.
     Scubapro has continued to develop its simple "unbustable" piston design to the point at which it is as complex as any other regulator, available in a variety of different metals and with a top price, too.
     Cressi-sub, not 10 years ago struggling to supply a regulator that would perform up to today's demands for CE marking, now claims it has a world-beater. Dacor, brought under the HTM (Mares) umbrella, makes its regulators in the HTM factory in Italy rather than in the USA.
     For those who want the American original, the Oceanic Omega II is a long-standing favourite. French pioneers of scuba, Aqua-lung, supply a line of regulators under the Legend label with a top-end model that will satisfy the buyer who wants something extra.
     And people will pay for that extra but, it seems, there is a limit. In recent years Mares took the highest ground with gemstone valve seats and solid titanium models but both its Ruby and the Ti Planet regulators are to be discontinued, presumably through lack of demand at the prices quoted.
     Atomic, a US company planning an imminent launch on the UK market, also first made its top-price regulators from pure titanium. These had the advantage of low weight and increased resistance to corrosion but, alas, were fabulously expensive and made from a metal that makes an unhappy bedfellow with high levels of oxygen, such that these regulators are said to be unsuitable for use with nitrox.
     Atomic supplied us with its latest design, the M1, made from a more modest but more nitrox-friendly metal. Mares suggested we took its traditional chromed-brass Abyss MR22 as its top-of-the-range valve.
     And, just to put things in perspective, we slipped the modestly priced Oceanic Alpha 7 with its basic piston second stage into the line-up. This was the regulator that won outright in the under-£150 price range. How would it compare in such auspicious company?
     As usual, we tested the regulators on the ANSTI breathing machine, but not before our four human testers had tried them all in identical and controlled circumstances, at depth, in the sea, and used them for many hours of diving. This provided us with a pressure/volume diagram for a typical breathing cycle of 25 x 2.5 litre breaths per minute done at an equivalent depth to around 50m (where possible) with an air-supply pressure of 50 bar.
     Some regulators came fitted with a breathing-resistance adjustment knob (BRA) and a venturi ± adjustment intended to stop exponential free-flows. Some presumably needed neither. In every case we tested with these adjustments, where fitted, set to give maximum performance.
     The results may surprise some of you.

The tests
Our team was extremely competent, with a wealth of diving experience gained both in the UK and at destinations throughout the world. I was there in my usual capacity as team selector, dive marshal and underwater adjudicator, and to record the event and its findings, taking photographs under water and making notes of spontaneous comments as soon as we surfaced.
     We were based at AquaSport in Taba, northern Egypt, a PADI 5-star Gold Palm Resort and a company that will be known to many readers from its 40-year history in Eilat.
     It kindly invited us to use its facilities free of charge and sponsored our activities at its dive-base at the Taba Hilton Resort. The quality of diving was a revelation and in fact threatened to be a distraction - we reveal all in next month's Holiday Special.
     AP Valves once again kindly supplied us with Buddy Tek Wing BCs with twinning blocks and bands so that we could easily employ independent twin cylinders.
     In this way we could equip each of the two buddy pairs with four independent regulators at one time, and these regulators were in turn supplied with two identical second stages so that two divers could simultaneously breathe, thereby putting the regulator under the maximum demand while at depth.
     As one might expect of regulators in this price-range, no-one could detect a difference in the performance of any of the regulators tested here whether one or two divers were breathing from it at any one time.
     The regulators were also employed inverted, as well as with the diver lying flat on his back in a face-up position. All these positions were tried with each regulator while at a depth of 40m-plus. Of course, each diver was free to switch between the two different regulators he carried at any other time during the dive and, in this way, our judges were able to eat, breathe and sleep regulators during the week of the test.
     What about the effects of nitrogen narcosis on our testers? Although all four test divers wrote legibly and coherently on their slates, and proved to be in general agreement on the performance of the different regulators, for the first time I conducted a simple test to try to gauge the effects of nitrogen narcosis.
     We went down to 55m, breathing air, and I gave out slates with a number of simple questions pre-written on them. These consisted of a mathematical calculation that had previously been successfully tried on an 11-year-old at the surface, and the request for the home phone number of each diver. Then I asked for the highest mountain in England (Scafell Pike) and the Chancellor of the Exchequer's name (Gordon Brown).
     Alex, the PhD student, got every answer correct but the others responded in a way that reflected more on their general level of knowledge (Snowdon is in Wales, Ben Nevis in Scotland) than the effects of breathing ordinary air at depth!
     We deduced that nitrogen narcosis was not affecting their judgment or performance.

Conclusion
At the end of five days of exhaustive testing and comparison the test divers had got to know each regulator pretty well. We then spent a day leisure diving, when each one could use the regulator of his own choosing. This revealed true preferences.
     First choice was clearly the Atomic M1, closely followed by both the Apeks ATX100 and ATX200 and then, in no particular order, the Aqua-Lung Legend LX Supreme, the Scubapro S600/MK25, and the Mares Abyss (let down only by an inappropriately small mouthpiece).
     Then there was the Oceanic Alpha 7 SP4, a great favourite. This begs the question, need you spend so much on a regulator when the inexpensive Oceanic Alpha 7 (although not recommended for use in cold fresh water) is so highly thought of?

CHRIS BOARDMAN, 34, world-record-holding cyclist and Olympic Gold medallist, has since become a regular Diver contributor, specialising in reporting on different diving courses. He was also a recent collaborator on comparison tests of both computers and fins. Chris already has more badges for diving than some people have logged dives.
CRAIG NELSON, 31, Boardman's faithful underwater lensman, is a full-time emergency paramedic based at Stoke-on-Trent and has four years' diving experience in both the UK and various parts of the world. Craig is a certified PADI Assistant Instructor, and has technical diving certifications from both IANTD and TDI.
ALEX VENN, 25, was hardened in dive battle during the last Gallipoli disaster (see account of liveaboard trip in Diver, November 1999). He has since left the dive-travel business to return to academia and pursue a PhD in fishology at the University of York, with research into coral bleaching. Alex is a PADI Divemaster and BSAC Dive Leader and has been diving since he was 14.
HUW WATSON, 42, formerly a mechanical engineer from Pontypool, South Wales, is now the manager of AquaSport International at Taba in Egypt, where the tests were carried out. Huw has been diving since 1976 in both the UK and at many international locations. He is a PADI Master Scuba Diver Trainer and has been a PADI instructor since 1991.