Review: Aqualung i300 Dive Computer

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Review: Aqualung i300 Dive Computer

Anyone who has done an Open Water or Advanced course with me knows that I feel that a dive computer is the single most important piece of equipment a diver should own. With a dive computer on your person, you have full control over your dive and are completely self-reliant – which is exactly what you, as a certified diver, should strive to be. A divemaster or more experienced buddy is good to have as an added layer of safety, but your safety is your responsibility and no one else’s.

Yes, it costs a little bit of money – but really, if you factor in the years of use you can get out of it, the annual cost is not that high. And having all the information not only improves your safety, but your confidence as well – and that means you are more likely to dive.

At this point, I can hear someone going “yes, but i can do this with a dive table as well”. Yes, you can, in theory. I did a dive yesterday – max depth 30m, total dive time 58min and at no point did we come anywhere close to our no decompression limits. If you were on tables, you would be out of the water in 24-25 min. Do you really want to pay thousands of dollars on vacation and then give up on >50% of your dive time? Let’s get real. Dive tables are obsolete for recreational divers and for good reason.

But I digress. Getting back to dive computers: until now, it really wasn’t cost effective to buy scuba gear, including computers, in India. However, times are changing. As those of you who are members of our Facebook group know, the scuba market in India has finally evolved to the point where manufacturers are taking it seriously, and now it is becoming increasingly cost effective for people to buy gear here.

So that led to me scouring the various price lists to see if there was a dive computer that could be a sensible alternative to the Suunto Zoop, one of the heavyweights in entry-level dive computer category – and this search led me to the Aqualung i300.

Before we start, a word on ‘entry level’ – that is not the same as ‘cheapest’. The idea is to find a computer which has sensible set of features ie, one which includes everything that is essential, and where you are neither paying extra for a bunch of optional bells-and-whistles, nor saving money by giving up on things that are important (be it features or usability).

Aqualung i300 Dive Computer


The Aqualung i300 is an over-sized dive computer which has 4 modes: Air, Nitrox, Free and Gauge. The first 2 are for diving, the 3rd for skindiving/apnea and the last for use as a bottom timer when doing technical diving.

The first thing that jumped out at me was that the i300 has user-replaceable batteries. This is a heaven-sent. My personal computer, a Suunto D9TX, requires me to send it to Thailand every time the battery runs out – which means a couple of months without it. User-replaceable batteries are a ‘must have’, in my opinion.

The i300 also comes with a bunch of useful features: backlighting (for viewing in the dark), auto-detection of altitude and fresh water/sea water, the usual depth and time alarms & 2 unique alarms: a ‘Dive Time Remaining’ alarm (which can be set to beep to however many minutes before you hit your no-deco limit) and a nitrogen loading alarm (which can be set to beep when you hit 20%, 40%, 60% or 80% of your max nitrogen loading).

It gets credit for having a sensible Dive Plan mode – on many computers, including several Suunto models, accessing the Plan mode during a surface interval would only provide the bottom time based on the current surface interval. So if you were 30′ into the SI and wanted to get in the water after another 45′, there was no way to figure out how much bottom time you would get then – the Plan mode would only show you how much bottom time you had at that time. Thankfully, the i300 lets you add more surface time to the planning mode, which makes it actually useful for figuring out how long you have to wait or what your depth/time limits would be when you actually got into the water.

Two other neat features – it has a ‘Deep Stop’ option you can enable, if you want, and it also lets you specify the depth and duration of your safety stop.

In addition to the above, the Aqualung i300 also has all the other usual features – dive log mode, total number of dives logged, a conservative factor setting (which lets you make the computer more conservative), metric/imperial adjustments and the ability to sync with a computer with an optional cable (this lets you download your dives for review on a computer or online dive log software, and also lets you upgrade the firmware of the device if need be) and auto-on – although for some inexplicable reason, you actually have the ability to turn off the ‘auto-on’ function, if you so desire.

Lastly, the i300’s Free Diving mode is quite robust: not only does it includes things like a Countdown Timer (before you start your immersion), but the computer actually tracks your activities in Free Diving mode. So that means you can switch from Free Diving mode to one of the Diving modes (Air or Nitrox) at any time – many other computers, including several Suunto models, require a 24-48 hour waiting time before letting you switch modes.



All of this is well and good, but ultimately, the main purpose of a dive computer is to help you plan and execute your dives. How good is the i300 at this?

Let me take a step back and sign a paean to Suunto dive computers. They are one of the heavy-weights of the dive industry, and with good reason – sophisticated computer models, workhorse reliability and smart interfaces. However, the big knock against them has always been how overly conservative they are – they use a very advanced model called RGBM, which tries to predict and minimize silent bubble buildup in the body, but the downside to this is that your dive time is greatly reduced, especially on repetitive dives.

The i300 is made by Pelagic Systems – who also make dive computers for Oceanic, Mares and others, and who are one of the leaders in developing decompression algorithms. The i300 uses their PZ+ algorithm, which is a moderately conservative algorithm, slotting in between the liberal DSAT model (also created by Pelagic) and Suunto’s conservative RGBM model.

So in theory, this should give you more bottom time, especially on repetitive dives.

But hold on – isn’t it better to have a more conservative computer? I sort of agree with that – their extra conservative model is the reason we use Suuntos in our dive center, after all.

However, the decision-making for a dive center is going to be different from the decision-making for an individual: we have to take into account divers of all body types, fitness level, age groups, health levels and abilities. You only have to take into account yourself.

And the inescapable fact is that millions of people have been diving safely for years using variations of the Buhlmann model (which is the compartment-based model that you learn in Open Water and even Divemaster), of which the PZ+ is a derivative. So at what point is a computer conservative enough?

Suunto themselves recognizes it to some degree – on their higher end computers, such as the D9, they offered a setting which would let you make the computer less conservative.

Generally, my belief is this – unless you have a condition which requires you to be more conservative when it comes to DCS (age, fitness, overweight), the PZ+ algorithm is going to be more than adequate at keeping you safe – just be careful about watching your ascent rate, give yourself atleast an hour between dives and follow all the concepts of safe diving that you learn in Open Water, and you are good to go.



Over the past few days, I have taken the computer for a bunch of dives, along with my Suunto D9TX and a Suunto Zoop from the dive shop. To test how the computers responded to various diving situations and emergencies, not only did I do a day of regular diving, but I also took all 3 computers into decompression, and did a day of reverse profiles (a shallower dive first, a deeper dive second).

The computer behaved pretty much as i expected: on the first dive, I got a bottom time that was somewhere in between my D9TX (which has the reduced RGBM algorithm) and the Zoop (which has the full RGBM algorithm). The difference between all 3 computers was fairly small. On the second dive however, the i300 gave me a little bit more bottom time than the D9TX, and both gave me significantly more time than the Zoop – this is pretty much what I expected, given the algorithms.

The backlighting worked well, the tactile buttons were a pleasure to use, and all the automatic features of the computer worked precisely as they were supposed to. And the readout is very clear and easy to read, with all the essential information available at a single glance.

On the reverse profile day, the same held – all 3 computers gave readouts that were ‘sensible’, with similar bottom times as earlier.

On the decompression dive, there was a significant variation, however. I went down to past 40m and hung around till all 3 computers went into deco (no significant differences in bottom time here) and started to ascend once both computers were showing me 5′ of ascend time. As i ascended to a shallower depth and the controlling compartment changed, the Sunntos gave me credit for off-gassing on the faster compartment and the deco obligation cleared by the time i was at 15m. However, the i300 obstinately kept that deco clock ticking till I ascended to shallower than 10m.

This is a key difference – the Suuntos are designed for decompression diving (provided you are trained and qualified to know how to use them for this), whereas the i300 is strictly for recreational, no-deco dives (and it doesnt pay any attention to that ‘recreational deco’ nonsense) – So someone who is a technical diver or planning to become one may prefer a different computer. However, for the vast majority of recreational divers, this isn’t such an issue. You shouldn’t be going into deco anyway.



2 weeks ago, if you had asked me to recommend an entry-level computer, I would have blindly said Suunto Zoop/Vyper – why? Because i am a long-time Suunto user – and Suunto is also the brand that we use in the dive shop, with excellent results.

However, while the Zoop still makes sense for the dive center, I think that for an individual diver, the slightly less conservative algorithm of the i300 makes it a better buy, especially given that prices are comparable.

There are a couple of cheaper options out there, such as the various 1-button dive computers like the Mares Puck. However, going back to what i wrote earlier about the difference between ‘best entry level’ and ‘cheapest’ – single button interfaces are a pain in the rear. Given that the monetary savings would have been very modest, I ruled those out.

There are also more expensive options out there – what a greater price gets you is a smaller form factor (so you can wear it like a wrist watch – which is actually a really good thing: it goes with you whereever you go, so you are sorted if you make a last-minute decision to go diving somewhere), air integration via optional tank transmitter (so you can see how much air you have left, both in bars and time, based on your breathing rate), an in-built digital compass (that’s nice to have for serious divers and pros) and, at the highest end of the scale, the ability to switch gases between various nitrox and helium blends and rebreather modes (useful for technical divers).

All those features are nice to have, and if budget allows, by all means go for it. A Suunto D6 or equivalent is a great buy in that price range. But if you are a casual recreational diver who is not looking to spend a huge amount of money on unnecessary gear, the Aqualung i300 gets my vote as the first piece of scuba gear you should own.

Buy the i300 at a special price


Scuba Diving Articles

Deep Sea Diving India

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Deep Sea Diving in India


DIVE INDIA at Havelock, Andaman and Nicobar Islands

Scuba diving, or ‘deep sea diving’ as it is popularly known in these parts, is a sport consisting of exploring the underwater world using Self-Containing Underwater Breathing Apparatus (S.C.U.B.A.). At the recreational/sport level, it is conducted from depths ranging from 5m to 40m.    Beginners can experience the thrill and excitement of deep sea diving by doing an Intro to Scuba program, whereby they get a guided dive with a dive professional up to depths of 12m. Those interested in a richer/more extensive scuba diving experience can do the Open Water certification course, a 4-day program which trains them as scuba divers and includes atleast 4 open water dives in the ocean.
Diveindia is the pioneer of scuba diving, in the Andamans, India’s largest scuba diver training center and India’s first scuba diving instructor training facility. Our highly-experienced team (which includes 2 full-time instructor trainers on the staff) has developed a unique training curriculum which takes the standard Open Water course taught across the world and builds upon it to provide one of the best beginner certification programs you will find in Asia. We also conduct daily deep sea diving programs for beginners who just want to try scuba diving and experience breathing underwater – catering to all skill, fitness and comfort levels (including nervous divers!).
If done properly, diving is an extremely safe sport and we take great pride in not just meeting but exceeding international safety standards when it comes to diving safety.

Come experience Deep Sea Diving in India at Havlock, Andaman and Nicobar Islands with DIVE INDIA


Scuba Gear Recommendation for Beginners

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Scuba Gear Recommendations for Beginners Posted by Vandit Kalia |

There is a common – and prevalent – belief that beginners need to buy a lot of equipment right away. Pretty much everything is touted as “essential for survival”, and so divers are urged to have their own gear so that they don’t have to rely on questionable rental equipment.
Another oft-cited statistic used to justify hard-selling equipment is that divers that own scuba kit are more likely to dive than divers that don’t. To me, this is a very silly stat which confuses cause and effect – is it owning gear that makes people more likely to dive, or could it be that the people that purchase gear are the keener divers, who will be diving more anyway?
Preying upon the insecurities and fears of new divers or relying on misleading stats may help the dive shop sell gear, but is it necessarily the best thing for the diver? I humbly suggest to you that buying all your gear upfront is NOT the right thing for beginners to do.
Don’t get me wrong – I am all in favor of divers owning their own equipment. The benefits of this are manyfold – you get gear that has more features than rental equipment, you can configure it exactly the way you want, it will fit you properly and most importantly, you can really fine tune your weighting and trim with your own gear. A keen reader will notice safety is nowhere in this list… and with good reason: having dived almost all over the world, I have yet to encounter a professional dive center with unsafe gear.

What to buy first?

If you can afford your own kit at once, by all means go for it. It is nice to have everything at once, and you can probably get a better deal this way as well, as opposed to buying piece-meal. However, what do you do if budget is tight and you cannot buy everything?
The traditional recommendation is to buy your own regulator, as it is “life support” equipment. I disagree. I have yet to see any dive center anywhere in the world whose regulators are “unsafe.” In fact, rental gears in most places are probably better maintained than a lot of personal regs. Also, remember that the biggest cause of reg failures is not lack of servicing, but manufacturing flaws in the gaskets, O-rings, etc. These usually come in defective batches, and a dive centre using lots of regs daily is far more likely to isolate and resolve this than personal regs, which probably do not get used more than 50-60 times a year. And besides, if you cannot trust the regs of the dive centre you are diving with, you probably shouldn’t be diving with them in the first place.
My personal recommendation is as follows:
Start by buying a set of mask, fins & snorkel. These are personal items where fit is essential, and it is always good to have your own. I recently got back from a dive holiday where I was using rental fins (I couldn’t locate the pair I wanted, and so had to rent) – while they got me from point A to point B, they were too soft for my legs, and didn’t provide me the thrust that I was used to from my longer, stiffer fins. I was always aware of them, and they intruded a little into my enjoyment of the dive.
If you plan to dive in cold or temperate waters, start by getting your own thermal protection suit. If you dive tropical locations, you can get by with rentals, in which case move on to the next item on this list. However, for colder water, a wetsuit or drysuit that has been carefully selected for fit and thickness can make the difference between years of enjoyment of the sport or quitting it entirely. Another reason to get your own wetsuit is so that you can learn the buoyancy characteristics of that suit and how many kilos/pounds of weight you’ll need with it. Suits vary greatly in their buoyancy, depending not only on their thickness, but also the type of neoprene used. Your own suit makes it easy for you to fine-tune your weighting to the bare minimum. And as an added bonus – you only have your own pee in it!
After you get a thermal protection suit – or if you dive tropical waters only and so are ok with rental suits – the next step is to get your own dive computer first, especially if you plan to do reef diving. If you plan to dive wrecks, you can get by jes’ fine with using dive tables, but for reef diving, dive tables are clunky to use and pointlessly limit your dive – not only do they limit your bottom time, but they also limit your flexibility during the dive. This recommendation is sure to draw gasps of horror from experts on many Internet forums, so rather than digress here, please read my article on Tables or Computers for my thoughts on this subject. Getting back to the subject – a dive computer lets you get the most flexibility out of your dive, and at the same time gives you all the information you need in order to truly be in control of your own dive.
A lot of people are content letting themselves be led around by the DM. This is may be safe enough in practice, but as a diver, you re responsible for your own safety. Delegating this to the divemaster is an abrogation of your duty and responsibility as a diver. Having a computer puts the responsibility for your safety back where it belongs: with you. I cannot stress enough how important this is.
The next item would be to get your own BCD. Why? Because BCDs vary greatly in their fit, comfort and stability underwater. And these are very personal preferences. For example, thousands of divers swear by Buddy BCDs – I cannot hover horizontally on them if my life depended on it. The additional features of personal BCDs are nice to have as well – for example, trim pockets, which let you redistribute your weight more evenly (few rental BCDs have this feature) or personalized attachment points for your octo, SPG, knife, etc. Lastly, with your own BCD, you get familiar with the rate of inflation and deflation, and so it becomes easier to adjust your buoyancy underwater.

A regulator would, in my opinion, be the last item to get.

What to look for in scuba gear

Masks: Quite simple and obvious: fit. You want a mask that doesn’t let in water. And you want one that is comfortable for the entire dive – even if the mask doesn’t leak, it can vary significantly in comfort, especially around the nose pocket. The last benefit of your own mask is that you can make sure it doesn’t fog, by using toothpaste and/or burning the inner surface of the glass with a lighter. And when you get a mask – make sure you also get a neoprene strap to replace the rubber strab that comes with it.
Lastly, remember that the most expensive mask is not necessarily the best. The mask I have used for my last 600 dives cost me $12. The mask I stopped using after 5 dives cost me $80.

Fins: Fins don’t get the attention they deserve, which is surprising, as few things can ruin your dive as much as fins that don’t match your leg strength, kicking style and dive conditions. Some fins are designed for people with strong legs – they require a lot of strength to kick, but give you a lot of power. Other fins are designed for people with less well-developed swimming legs – they are softer but give you less thrust. Nowadays, there are a lot of expensive split-fins, which claim to reduce effort without compromising on thrust… but there, the trade-off is price. People who use the flutter kick would be better off with different fins than people who use the frog kick. Ideally, what you want to do is try out a range of fins at your dive centre or borrow some from your friends, till you find something that matches your legs/kicking style.

Do not spend a lot of money on fins unless you know you’ve found a set that works for you. Rent or buy a pair of cheapies in the interim, if need be.

Computer: Virtually all computers do the job from a safety point of view. Size, user-replaceable batteries, Nitrox capabilities & air integration are some of the features to look for. If you are on a budget, a basic Aladin or Suunto Mosquito does the job, and does it very well. I like wrist-mounted watch-style computers as I wear it when I go traveling, and am less likely to forget it. Others prefer bigger computers for ease of viewing the screen. Yet others prefer computers that are attached to their regulator console – one less thing to strap on while getting ready for a dive. The good news is, there really is no bad computer in the market today.

BCD: This is where it starts getting personal. Literally. There are three things you need to take into account with BCD. The first one is lift – ie, does it have enough buoyancy to support you during the dive. For tropical water diving, ie, with a 3mm suit, this is a non-issue. But if you plan to dive with double steel tanks and a 7mm two-piece wetsuit in cold water, you better look into the lift capacity in more detail. At the start of the dive, those tanks will be quite a few kilos heavy. And as you descend, your wetsuit will compress and you will become even more negatively buoyant. It is possible to be as heavy as 10-12kg negative at depth at the start of some dives. Can your BCD support that? After lift, the next feature to consider is features: are the pockets easily accessible, do you need weight integration, does your BCD have trim pockets (essential,
in my opinion),
etc. The third item is personal fit. Some people like back-inflating BCDs, some like the classic stabilizing jackets where the air moves about everywhere and some like the back-and-side pockets of modern BCDs. If possible, try before you buy. Only in the water will you know if a BCD rides up on how, or if the pockets are really accessible or no.

Btw, one hot new thing in the recreational diving community these days are backplates and wings – basically, tech-diving gear being used by recreational divers. However, you can get all the benefits of BP/wings even with traditional BCDs – the main features to look for are a back-inflation bladder and a crotch-strap to keep the tank from riding up. This way, you also get the benefits of quick-releases (let’s face it, if you aren’t going to be putting twin-100s and 2 stage bottles on your harness, a QR is actually quite a nice feature to have) and pockets for keeping slates, safety sausages, etc. Of course, you lose the whole “bad boy techie” glam, so not everything in life is free. And before the inevitable “try it first” emails come in, I should point out that I dive in BP/wings myself, and have been doing so from the days when DIR was an MS-DOS command, not a dive cult. I even teach OW in them. But I think for a lot of recreational divers, something like the Dive Rite Transpac is probably a better bet than full-on BP/wings.

Regulator: I am going to get a lot of hate mail on this, but I have a simple theory regarding regs and recreational diving -it doesn’t matter a whole lot what you get. Balanced, unbalanced, piston, diaphragm, breathing resistance and what have you… you can spend months and months analyzing the minute details of these various features. Yes, one reg may be marginally easier to breathe at 40m than another. Yes, in some sort of an extreme lab-created situation, you might be able to over-breathe a reg (although if that situation were to happen in real life, you’d have a lot more pressing problems than you reg). In practice, even a good entry-level reg ill give you decades of service.

Design and innate reliability of one brand or another are not an issue either for most typical regs. I have taken apart and serviced Oceanic, Apeks, Beuchat, Scubapro and Aqualung regs. The basic concept of a reg is pretty much the same for a given design family (piston/diaphragm, balanced/unbalanced). So it isn’t as if that is a huge concern. Note, however, that I did a “most typical regs.” There are a few brands which are exceptions to this rule, but those are the “exotics.”

One area where there is a difference is in maintenance requirements – some regs are more finicky and need to have their IP adjusted and washers, etc. changed regularly or they develop leaks. Others just work and work and work, regardless.

If you do cold-water diving, things are different. You will need a higher-quality, environmentally-sealed reg. And in this case, there are differences between brands, so do your research before you buy.

The above consists is my personal recommendation on what gear to get, when & how to go about the process of selecting gear. However, one question I get asked a lot is what specific brand or model to get. There really is not single “best” choice out there. However, some quick recommendations based on my experience:

Mask – no recommendations can be made, as it is too personal a choice

Fins – Cressi Frog series for frog-kickers; Mares Quattros for general all-purpose use; Atomic Split Fins for people with weaker legs or requiring a lot of speed, especially in calmer waters

BCD – Anything by Seaquest. Excellent BCDs. The Waves are hardy, budget BCDs which will give you YEARS of service (we use them at our dive centre and a more trouble-free and comfy BCD I have yet to encounter). They don’t have trim pockets, but you can buy trim belts to attach to a tank anyway. At the higher end, the Pro/Pro QD/Black Diamonds are all excellent BCDs.

Regulators – Apeks. There is no reason to look for anything else. My own regs are about 8+ years old and were last serviced in 2003. I’ve taken them to 94m, taken them ice-diving and done over a thousand dives on them. All they ask from me is a quick rinse after a dive. Now that’s love!

Computers – Aladin/Uwatecs or Suunto. It is like the great “Landrover or Landcruiser” or “Canon or Nikon” debates. You really don’t wanna ask. Just go to a store, look at them, and see what you want. Suuntos have a nicer form factor (you can wear them as a watch) and you don’t have to suffer that hideous monstrosity of an interface that the Aladin/Uwatecs do. On the other hand, Suuntos are a bit too conservative – almost ridiculously so – especially the newer ones. It is sort of like diving with your mom telling you to be careful, put your hat on, wear your scarf. The Aladins have a more realistic algorithm (which is perfectly safe, I might add). Ultimately, both are quality devices where is really counts – keeping you from getting bent.

The above brands are good, and you cannot go wrong buying them. However, that is not to say that these are the “best” or that other brands aren’t as good. There probably are a lot of other fins, BCDs, etc. that are just as good as the ones I mention above… and some may even be cheaper.

The good thing about scuba is that there is a plethora of opinions out there. I can bet you a lot of divers – including those with a lot more experience than me – feel differently and would suggest that you go the traditional “get your own reg first” route. Others, no doubt, would be horrified by my blasphemy about “all regs being more or less equal in the water for recreational diving.”

But these are my opinions and are not biased by anything – we don’t sell equipment nor do I get any commissions from any of the brands I recommend above (although if they feel like sending me some goodies, they are welcome to do so!). So you decide how much credence you want to give it.