John Bantin has been a full-time professional diving writer and underwater photographer since 1990. He makes around 300 dives each year testing diving equipment.

"Microbubble" is the current buzzword among diving-computer algorithm writers. Physiologists have discovered that nitrogen coming out of solution in your body during decompression tends to form tiny bubbles in your bloodstream rather than diffusing directly to gas at the alveoli in the lungs, as was once thought.
     So there you are, letting a few of these microbubbles rattle round your system at the surface after a dive when you decide to pop back in and add a few extra with a repeat dive.
     These sub-clinical microbubbles may not give you any symptoms or cause any damage but they are very friendly towards each other. Given half a chance, they get together with any new bubbles you might make and form bigger ones. And if that happens - whammo! They party, and you're suddenly taking a ride in a helicopter to that friendly man with the small iron room closed by a big door.
     So the latest generation of computers has algorithms that take this into account and gives you reduced no-stop times and increased deco-stops for repetitive dives, to help prevent the worst from happening.
     The Uwatec Aladin was once the diving computer by which others were judged. In recent years, however, its popularity has waned, to the advantage of companies making computers that take more notice of the consequence of repetitive diving on existing microbubbles in the body.
     The effect is that those using older computers are out of the water, showered and changed for dinner while those using new-wave computers are still hanging about, going crinkly in the shallows.
     There may be some bold young divers who think that being first at the dinner table is important. Call me old-fashioned, but I opt for caution when my health is in the balance.
     But it's not goodbye Uwatec Aladin and thanks for all the time with the fish. The vast range of Aladin models with the Buhlmann ZH-L8 ADT algorithm continues alongside a new generation of Uwatec Smart computers with the new ZH-L8 MB. This incorporates more advanced recognition of the circumstances that cause the formation of microbubbles.
     The user can select one of five additional microbubble-suppression levels, and have a better chance of beating his buddy to the shower.
     The new Scubapro Uwatec Smart Pro looks like the Aladin Pro Ultra, with its built-in screen-guard and adjustable elasticated strap, but it has some new features.
     These include a "unique" 32-bit microprocessor which gives the facility for a faster sampling rate than before, plus the increased memory that is essential to go with it. While some computers sample the circumstances of your dive twice a minute, the Smart Pro computer checks depth/time details up to 120 times a minute for fine-tuned calculations.
     When it comes to downloading this on to a PC later, a 4sec sampling rate is used for practicality. The SmartTrak software for this is included with the computer.
     Other advances include an infra-red wireless link to the PC, a more easily read LCD, a nitrox function that can be set in 1% increments from 21% to 100% O2, a gauge mode for those not using other gas mixes, and a user-adjustable maximum-depth warning.
     To meet the added-value challenge from competing brands, the Smart Pro also displays water temperature. There are only three water temperatures so far as I am concerned: comfortable, cold and I'm out of here! A more useful icon is the one that tells you to what altitude you may climb after diving, invaluable for anyone who has to drive over a mountain on the way home.
     In the inevitable direct comparison to the Suunto RGBM100 algorithm used in the Vyper, the Uwatec Smart with a "normal" setting seemed slightly more cautious for a first dive but a lot less cautious as one got into a series of repetitive dives.
     I guessed rightly that it was the same as the original Aladin Buhlmann ZH-L8 ADT algorithm.
     Choosing one of the five more cautious microbubble levels will bring the Smart Pro closer into line, and possibly well behind it. However, pre-selection of which MB level is right can only depend on personal experimentation and the gut-feeling of the user.
     The computer also introduces the "level-stop", said to be there to avoid microbubbles, marked MB. This is in addition to "deco-stops", but the difference is not explained.
     Level-stops can be as short as a minute and cut in at depths deeper than you might be used to. However, I only saw a level-stop come up at 3m and, for me, a stop is a stop. I guess that missing a level-stop is not as bad as missing a deco-stop.
     You have to choose to set an "MB-level". I used the Smart Pro for a week before I realised that I was missing this important feature. The manual explains how to change MB-levels but does not explain that this feature is not present at stage one.
     It also does little to explain how you should choose the MB-level that's right for you, apart from a vague reference to divers who might have a PFO, or hole-in-the-heart.
     In practice, I imagine this will depend on the computer your buddy is using and whether your surface interval is shorter than you would otherwise like. This might happen on a paid-for two-tank dive on which other divers have been a lot shallower.
     After exhaustive testing and comparison, I found that MB levels 1 and 2 approximated the same result in the stops that were required by the Suunto RGBM100.
     With these MB levels, level-stops often showed up as being needed at 3m while I was at, say, 20m, but cleared off long before they became significant.
     Most divers who buy a Smart Pro will probably never get round to selecting any of the MB-levels and will happily go on using it just as they would have used the older Aladin range. And why not? It seems to work!
     I used to find the Aladin computer display one of the clearest to read, though there are certainly now some more legible ones on the market. The Smart Pro proved slightly less than clear when it came to setting up the unit with my personal preferences. I needed a magnifying glass to interpret the icons.
     Uwatec has once again stuck with wet-contacts for all the Smart Pro's operations, but with so many rivals now using two or three buttons, this is no longer finger-licking good enough. Scubapro/Uwatec will surely have to follow the trend sooner or later. And operating the unit between dives was not as intuitive as is a menu-driven system, and I resorted to carrying the instruction manual with me.
     You need to interface the Smart Pro with a PC to change some of the user settings such as maximum PO2 level. Many divers who buy the Smart Pro might already be fans of Uwatec products and own the SmartTrak interface, but the manufacturer includes the necessary software as part of the package.
     I understand there will shortly be a Smart Com, the Smart equivalent of the older Aladin Air and air-integrated by hose. Surely a radio-linked Smart equivalent to the Aladin Air Z cannot be far behind.
The Scubapro Uwatec Smart Pro costs £375.

How to stay dry and socially acceptable
Is the Pope a Catholic? Do bears defecate in the woods? Is silicagel commonly used to remove moisture from packed and sealed consumer durables? I think you know the answers to all these questions.
     Now if, when you unpacked your computer, your camera, your music system and your camcorder, and all those other lovely shiny new items you have bought, you had thought to keep the little sachets of silicagel, you might not need to buy the useful product I am going to tell you all about.
     However, most of you simply threw the little sachets away and the rest probably thought it was sugar and wondered why your tea tasted funny.
     Like many good ideas, this one is so obvious I can't understand why I didn't think of it first. Silicagel has the ability to soak up moisture from the air around it, so proves an ideal medium for drying out inaccessible areas, like the inside of your drysuit boots. Once it has done its job, you can dry it out again by putting it in an oven or microwave.
     Dampire is an example of imaginative packaging. The manufacturer has provided the customer with a useful amount of silicagel (around 600g) packed inside a water-permeable bag and attached to a 2m piece of webbing with clips. You simply lower the bag down the leg of your drysuit and leave it to sit inside your boot. The bags come in pairs, in an air-tight jar.
     So why are your boots wet? Well, putting aside the fact that most drysuits leak to some degree and the water migrates by gravity to the lowest part, you also sweat while wearing your suit and this moisture is a great breeding ground for bacteria. When I was a kid, a well-known soap advertised its virtues with a friend whispering in some unfortunate's ear: "B O!"
     Today, with the modern habit of taking regular baths or showers, it's more likely to be Boot than Body Odour. Your best friend might not wish to tell you this but, in the tradition of this magazine for telling it like it is, I'll tell you that your drysuit boots stink!
     I proved that the Dampire theory works when my wife dropped her phone in the bath. I put it in the Dampire jar and it was dried out before I knew it. It didn't work any more, but that's the story of electronics! Thankfully, drysuits are low tech.
     So when buying a drysuit, it makes sense to buy a Dampire kit too. It might just keep you and your suit socially acceptable. Just be careful when re-energising the packs that you don't become over-enthusiastic with the heat control and melt the plastic fittings.
Dampire costs £20

There's simple - and there's simple
No-nonsense northern with a hint of the east
What is Sweden famous for? Cars built like trucks, trucks built like trains, stainless-steel, Freddie Ljungberg and chunky home-assembly furniture. What things from Sweden have in common, save for items bought at IKEA, are that they tend to be expensive. But they are built to last. Some would say they are unbustable!
     In the world of diving, Poseidon regulators have had an unbustable reputation for years, and it would not be wrong to assume that any other product bearing that brand should be similarly strongly made.
     Of course, with our one-world economy, the fact that a brand comes from the icy north of Europe might well disguise the fact that the product is manufactured in the tropical Far East. But wherever it comes from, the Poseidon Photic NHV looks as if it should come from Sweden.
     It's a very conventional BC with few surprises but it does have an integrated-weight system with ditchable pouches each side. These take at least 5kg each and follow an almost conventional format, with overlapping rip-away velcro flaps and toggles.
     Take great care to check that these flaps are closed properly before every dive, because once you get out to sea and they become saturated with salt and sunshine, they can curl and lose their ability to grip.
     This goes for all velcro-flap integrated-weight systems. Trim-weight pockets with pinch-clips at the rear can take extra weight should you need it. Lead stowed here helps a lot when trying to stay comfortable while using an aluminium cylinder running close to empty, and I was able to avoid that floataway-tank sensation.
     There are two tank cambands, so you can be doubly sure not to drop your tank during a dive. They are threaded through a hard backpack. The elasticated harness is similarly threaded so that the buoyancy chamber is an entirely separate unit.
     This does not, however, mean that the jacket inflates away from you. Under water I distinctly felt the air inflate what feels like vertical air-chambers running either side of my back and the attached tank.
     That said, when it was fully inflated at the surface, I was not caught in the expected unbearable hug.
     If the cummerbund is too long, you can easily shorten it by reconnecting the inner ends, which fold back on themselves. There are six large D-rings with three smaller ones along the bottom edges.
     I don't understand the thinking behind the pockets. There are two average-sized side pockets closed by velcro-covered flaps, and as any diver knows, things stored in these will not be 100% secure once inverted during a dive.
     Above these there is access to two self-draining zipped pockets, but they are probably only 5cm deep, and useless for anything I might want to take with me on a dive. Why not simply have two large zipped pockets?
     The direct feed neatly integrates with the corrugated hose and this is topped off with a pull-dump valve. The opposite shoulder also has a pull-dump and there is another at the lower back, with its pull-cord neatly threaded through to a toggle at the front. This last proved eminently useful when descending head-down from the surface in a hurry.
     All the fittings look suitably Volvo-like, and large light-reflective patches at the shoulders complete the picture of something that always travels with its lights on.
     I always ask for any sample BC to be sent to me in size M, because although I am tall I have avoided a life-time of fish suppers and brown ale.
     However, this BC in size M was probably a little small for me. I could not have used it conveniently with a bulky drysuit. I used it with a wetsuit without problems, but I might have found size L easier to get into once rigged with a tank and before diving. This hints at product sizing in the Far East rather than in Viking Country.
This BC represents a very conventional approach to design. Things might be expensive in Sweden but the Poseidon Photic NHV is not. It costs a surprisingly good-value £258. What does "NHV" stand for? Northern Hemisphere Version, of course!

The mirror tells no lies - or does it?
Visualise, if you will, a line of people waiting to board a ski-lift at Val d'Isere - stylishly dressed, brightly coloured, chic. Now visualise a typical group of divers queuing to board an Egyptian day-boat. I think you've guessed what I'm getting at.
     Why is it that, when it comes to style, we usually have more in common with those sad folk who hang around the perimeter roads of airports, noting down the registration number of every 767 that thunders overhead, than with those participating in other expensive activities such as ski-ing, golfing, yachting or even surfing?
     Is it because scuba-diving attracts the visually unaware? People for whom the privacy afforded under water becomes a comfortable barrier to the public gaze? As a photographer I am acutely aware that very few people casually encountered during a dive will enhance my photographs by being included.
     Is it because, in paying your dues during training by changing behind the Cortina in the car-park, baring all to the world while avoiding the dog faeces, any vestige of self-regard, of care for one's appearance, is lost?
     In France, Yves St Laurent may be the epitome of sartorial elegance and Beuchat a well-known manufacturer of dive gear, but don't assume that French divers have more style than we do. They are worse than any Brit.
     A typical French diver sports a beard because he lost his razor. He scorns the use of a dive-bag when any old hemp sack will do. He checks that his regulator is working by blowing Gitanes smoke into it, and as for a suit... well, nothing but black, worn out at the knees, feels right. So when Beuchat sent me a wetsuit to try, I wasn't expecting too much.
     The Beuchat Focea is a one-piece 5mm suit with a rear zip. I asked French friends what significance there was to the name. The best they could come up with was that La Focea was the name of the luxury yacht formerly owned by a Mitterand minister who exchanged a distinguished career in government for an extinguished career in gaol.
     However, an Englishman living in France was able to tell me that Focea was the name of an ancient Greek outpost located at what later became Marseilles, where Beuchat is based.
     The Beuchat Focea is augmented by either a 2mm undervest, with or without hood, or a 5mm shortie (with hood) that is worn over it. You could wear both. There is very little science to it. You simply don the appropriate number of layers to suit how cold you feel.
     There are soft rubber knee-pads and the limb sections are contoured. This is a true wetsuit and there are no seals to speak of. It seems well enough constructed.
     When will wetsuit designers understand that what I want is a suit with 10mm of neoprene at the chest and biceps, physically nipped-in at the waist with 2mm neoprene, and with a contoured six-pack effect over the stomach?
     The Beuchat Focea uses clever visual tricks to make the wearer look slimmer and more shapely. Panels of neoprene in blue, black and shades of grey are set one against the other for full effect, with a nipped-in-waist, a broad chest and bulging biceps.
     I looked forward to acting the handsome cat at the dive-site. Instead, I relived an early experience that once occurred in the cramped rear quarters of a little dive-store in Fulham Palace Road. I was eventually found, blindly stumbling among the packing cases, half-in and half-out of a too-tight suit, sweating profusely and yelling in muffled tones: "Will someone get me out of this!"
     The crisis of trying on a tight-fitting garment in an inappropriate setting is enough to make us dismiss any visual shortcomings. A suit that fits is good enough.
     The Focea sent proved uncomfortably tight for me, so you will just have to be content with a "test-at-the-desk", in the style that certain other magazines seem to consider acceptable.
The Beuchat Focea is available off-the-peg. It costs from £166 (7mm) or £137 (5mm). The shortie vest and hood costs £85.