[Dive computer] buying advice

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It is possible, and you may've had it replaced because it was limiting your bottom time (and not for some other reasons), but you don't actually know this. Knowing what you know now, you think you would have.

i bought a new zoop for my first dive trip which was a month after i finished ow. it went into deco 2 times during the trip. i sold it after i bought a used oceanic computer off someone from this board.
 
Fair enough. I may have missed that bit when I was shopping for ours, I forget. I do remember considering a zoop back then. I would not have bought one in the first place if I were aware of it, but if I did, that'd be the reason to replace it, yes.

The Zoop Novo (i.e. the "new" Zoop) does have gauge mode, as far as I understand. So, that reason doesn't really apply to the OP. But, the suggestion to have a basic understand of what the different algorithms pros and cons are does still apply.
 
But, when you are shopping for a computer, and you, one, want to ensure you get maximum bottom time, and, two, want to do your best to ensure you don't want to replace your computer any time soon, then why would you not consider the algorithm as one factor in your purchase?
If getting the maximum bottom time is your primary criteria, then you would want to consider the algorithm. But not everyone's going to make that their primary criteria ... and, to my concern, purchasing a dive computer based on maximizing your bottom time isn't a good choice of priorities for a new diver.

The irony (to me) is that you would specifically recommend getting one that supports Nitrox for the stated reason of not having to replace the computer soon. But then would counsel to not worry about the algorithm, when it seems pretty clear that a very common reason for replacing a "first" computer is to get one with a less conservative algorithm.
That may be a personal priority for you ... but I don't think it's as common as you make it out to be. Suunto is a popular brand ... even among experienced divers who have put thousands of dives on them.

If you are shopping for a computer and you have any concern for avoiding want to replace it soon, then wouldn't you counsel to pay attention to ALL the common reasons why people replace their first computer after a relatively short time or relatively few dives?
Yes indeed I would ... which is why I offered some criteria in my first post in this thread that had to do with criteria other than the bottom time concerns that was pretty much all you and a few others were wanting to talk about.

Sure, when you're preparing to go diving, there a lot of things to focus on for increasing bottom time - up to the bottom that NDL becomes the consistently limiting factor... But, what you are SHOPPING for a computer, then all the factors that are common reasons to replace one seem like they should be considered. You could still choose a conservative algorithm, but I think that choice should be based on information, not ignorance.
I agree ... so other than the computer's algorithm, what other criteria do you think should be considered?

... Bob (Grateful Diver)
 
the suggestion to have a basic understand of what the different algorithms pros and cons are does still apply.

While I fully agree in theory, I don't live in theory. Here where I live, what are they? Aside from handwaving with a few of us stating "brand X is horribly conservative" and a few others claiming "I dive brand X and have never felt limited by it". (And don't quote the scublab numbers because you already know I don't believe they prove anything other than you can game a computer to display different numbers.)
 
If getting the maximum bottom time is your primary criteria

I agree ... so other than the computer's algorithm, what other criteria do you think should be considered?

... Bob (Grateful Diver)

You'll notice, if you look at all my posts in this thread, I never recommended a computer. I also never said maximizing bottom time should be a top priority or primary criteria.

I simply said that when someone buys a new computer that is a characteristic of the computer that they should understand. I also said that a common reason I've seen for computers for sale in the Classifieds that are relatively new and/or have relatively few dives on them is that they are too conservative.

As for criteria that should be considered...

I find all this talk about algorithms a bit too much getting into the weeds, particularly for a novice diver who is going to be more limited by available gas supply than NDLs. I think pretty much any choice of dive computer is going to provide a safe algorithm for recreational diving, and that the whole issue of "conservative" algorithms is essentially overblown. If it's a concern, many computers nowadays come with a setting you can use to change the conservatism of the computer ... although there's a caveat there as well which is that before changing the default conservatism you should have some idea (through experience) of how it's going to affect your physiology ... and what factors might cause you to want to dive a bit more conservatively on any given day.

What a newer diver really should focus on purchasing is a computer that's easy to read, easy to set, and intuitive to understand what the numbers being displayed during the dive are telling you. And for almost all of us, getting one that's EAN compatible is important ... even if you don't currently use nitrox, because at some point if you should decide to you then won't have to purchase a new computer.

I agree that being easy to read, set, and intuitive to understand the numbers are all good. But, I think understanding the algorithm is equally important. Also, your statement that "many computers nowadays come with a setting you can use to change the conservatism" is incomplete and, thereby, misleading. With no further information, the reader would be left to believe that they can make a computer more conservative or less conservative and that is not true. All the recreational computers I know of come with a setting that only allows you to make them MORE conservative. If you buy a Zoop and it turns out to be more conservative than you would prefer, there is no setting you can change to make it less conservative.

Really, if I were to tell a new diver what criteria should be considered, I would say:

algorithm (not to be taken as a recommendation for liberal - only a recommendation to understand what you are choosing)
readability - to include that an OLED or LED display will be much more readable in low viz conditions than an ordinary LCD, but some OLEDs are really hard to read in bright ambient light conditions
mounting location - consider whether you want a console, wrist puck, or wrist watch
air integration - consider whether you want it or not. I feel like (anecdotal) another common reason for people to replace computers prematurely is a desire have air integration
Nitrox - should absolutely be supported, but not a factor except for older computers
Trimix - Recreational trimix seems to be becoming more common. Before buying a computer, the diver should probably evaluate their agency, instructor, and where they dive to figure out if trimix is in their remotely near future. If it is, they should definitely factor that into their computer purchase. Not many computers support trimix
Battery - coin? AA? Built-in rechargeable? User replaceable? Proprietary? How long will it run on a charge/fresh battery?
Tech - the diver should consider whether tech training might ever be in their future. If they think it might, and if they have the budget, I would suggest a Perdix above all others. Either a good used one, or a new Perdix AI. Buying a new Perdix (non-AI) does not make financial sense (to me). The user market has numerous, for cheap, and the Shearwater warranty is transferable. And even if they don't think tech training is in their future, the Perdix is still an excellent choice to consider.

And I would specifically add to NOT worry about:

multi-gas support
support for O2 over 40%

Even the less expensive computers are not cheap. I think buying a dive computer is a serious purchase that merits serious consideration and taking plenty of time to understand all the criteria I listed, then making an informed choice. There are lots of people that post about still diving computers they bought 20 or more years ago. If someone asks me for advice on buying a computer, I would try to help them arrive at a decision that they can have some hope of still being happy with in 20 years - not just for the next 6 months or a year. And if a person keeps diving for 20 years, I would think there's a good chance the algorithm will become important to them at some point during that time.
 
I have been using Suunto computers strictly for about fifteen years without any problems. I am switching from Suunto now primarily because Suunto computers are getting way too expensive for the features they have compared with other brands and also because it seems that Suunto is falling behind in technology and options for the diver. Other companies such as Oceanic, Shearwater, Ratio and Scubapro (and possibly D6) have much better products with MUCH higher value than Suunto. Suunto computers are just grossly overpriced especially when compared with Oceanic's computers (Oceanic computers have more convenient features and options at lesser prices).

For somebody who has been using Suunto computers since their first generation "Solution" computer in the early 90's, Suunto now isn't an option for me at all. I'll be phasing out my personal Suunto computers (I own several of them) as well as my Dive School's Suunto's and phase in computers from other vendors (different models with different features depending on the type of diving, e.g. recreational vs. advance recreational vs. technical, etc.).

The absence of Suunto's support and communications with its customers and its very poor handling of customer complaints and extreme stubbornness in addressing market needs are just too much for me now. This isn't about "algorithms" or about reliability issues at all, it is about other factors as detailed above. Suunto is simply not a good value anymore and not a pleasant dive computer vendor to deal with as a dive professional or a diver.

(Note: Oceanic and Scubapro have VERY attractive entry and medium level computers with very useful features and aggressive pricing. They are Excellent values compared with others when Suunto doesn't come even close.)
 
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Good list ...

There are lots of people that post about still diving computers they bought 20 or more years ago. If someone asks me for advice on buying a computer, I would try to help them arrive at a decision that they can have some hope of still being happy with in 20 years - not just for the next 6 months or a year. And if a person keeps diving for 20 years, I would think there's a good chance the algorithm will become important to them at some point during that time.

Depends on how often you dive, and what your long-term diving goals might be. Over the past 16 years I've gone through maybe a half-dozen dive computers ... plus the ones I've tested for a couple different equipment manufacturers prior to their production release. I didn't stop using them because I was unhappy with the algorithms, but rather because my diving took me places the computers were not designed to go. My current two are both trimix computers, with user-selectable algorithms and conservatism levels. And while either one of them would be suitable for recreational diving, they're both rather expensive options unless you are going to be using them for diving well beyond NDLs. Also, considering the pace of technology changes, I can't see hanging onto any dive computer for more than a few years unless you're using it so infrequently that you can't justify the cost of replacement. As for algorithms ... pretty much any computer you buy today will be using some implementation of an algorithm that didn't even exist in a dive computer 20 years ago. We've learned a lot just since I started diving in 2001, and modern equipment has implemented new strategies for making use of that knowledge.

... Bob (Grateful Diver)
 
Trimix - Recreational trimix seems to be becoming more common. Before buying a computer, the diver should probably evaluate their agency, instructor, and where they dive to figure out if trimix is in their remotely near future. If it is, they should definitely factor that into their computer purchase. Not many computers support trimix
I would specifically add to NOT worry about:
multi-gas support
support for O2 over 40%

A trimix computer without multiple gases for deco is not very useful.

For a first computer I suggest getting something cheap enough that in a few years if you decide you know what you really want you do not feel like you wasted a lot of money in the first instance. Also, if you leave it on the boat you don't want it too hurt too badly.
 
You can always take a proven safe liberal computer (maximum bottom time) and manage your dive in a more conservative manner if you choose. Really hard to make a conservative computer more liberal. I am still diving my 20 y/o Oceanic Data + and see no reason to make any change. Used ones can still be found for under $75. I really like the graphic display of tissue loading.
 
A trimix computer without multiple gases for deco is not very useful.

Are people with Recreational Trimix cert (I forget right now which agency does that) certified for deco? I thought those people were just doing NDL dives with TX for anything below 100'.

Anyway, part of my point was the person buying the computer should learn enough about computers to know for themselves whether they need to buy something that supports Trimix and/or multiple gases.
 
https://www.shearwater.com/products/peregrine/

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