Here are some guides before buying a dive computer:

Air or Nitrox

If you’re not currently diving using Nitrox but think you might in the future, you may want to get a Nitrox-compatible computers. Once you go for Nitrox diving, you can use the same computer and save your pocket from buying another computer. But if you are not planning to use Nitrox, a standard air computer will suffice, saving you a couple hundered of dollars compared to Nitrox-compatible one.

Stand Alone or Air Integrated

The latest technology of diving computer not only tells you information such as bottom time, depth and navigate you through its digital compass, but also provide you with digital reading of air pressure. High end dive computer such as Suunto D9 has an optional wireless cylinder pressure transmitter that can easily be attached to the high-pressure port of the regulator. A stand alone computer only provide depth and time, so you will require a separate pressure gauge. Stand alone computers however is relatively cheaper than the air integrated. The only drawback of the all-in-one computer is that if the computer fails during the dive, which is very unlikely even, you’ll lose the air pressure information as well.

Display Font Size

Having a computer when diving allows you to continuously monitor your dive information. But this will become useless if you can’t read the information displayed easily. The font size on the display is important – if the font is too small, then you won’t be getting the benefit of having a dive computer with you. Choose computer that displays all the necessary information only, and not the additional information that is not so important during your dive.

Activation Mode

Certain computers activate automatically once you start diving. But some needs to be manually activated with a press of a button. Make sure you don’t forget to press the button if it requires manual activation, or else you may need to go to the surface, hold the computer out of water and activate it. Once computer starts recording dive info, it continues to run until it shuts off (usually after 12-24 hours after you’ve completed the last dive), so computer activation is only an issue on your first dive of the day.

Power Source – Batteries

Make sure you identify the option when the battery dies. Many computer allows user to change the battery by themselves, but some may require specialized technician to do the battery change and others need to be sent back to the manufacturer. It will be such a hassle if you need someone else to do the battery replacement for you. Besides costing you more, it will be such a waste of time for you to get it done by the manufacturer. Remember to check with the shop or experienced user which uses the similar computer on the average lifespan of the battery because the last thing you want is having a battery drained while in the water.

PC Connectivity

If you’re a hard core diver, you may find it useful to have all your dive information on your home PC for your reference. But not all dive computer allows such PC interaction. Check with the dealer if the dive computer that you intend to buy has such capability. You may require a software to be installed on your PC/Notebook with an interface which gives you a graphical display of your diving.

As a conclusion, a dive computer is undeniably a very useful tool when you’re diving. There are quite a number of brands and models to choose, but what important is that you take your time to check around and do some homework before buying a particular dive computer.

Happy Diving!!