Dive Computers: I Use the Aqualung i770R and Want to Upgrade to the Garmin Descent MK2
My current dive computer is the Aqualung i770R with the wireless transmitter. It's a good computer. I've put it through a lot of dives and it hasn't let me down. But I'll be honest — I've been eyeing the Garmin Descent MK2 for a while, and at some point I'm making that jump.
Here's where each one sits and what actually matters when you're picking a dive computer.
The Aqualung i770R — What It Does Well
The i770R is a full-featured wrist computer with a color display, wireless air integration via transmitter, and support for multiple gas mixes including nitrox and trimix. For most divers, it has everything you need.
The wireless transmitter is the key feature on this setup. It reads your tank pressure and sends it to your wrist in real time — no hose, no console, no constant twisting to check a gauge. You glance at your wrist and you know your air, depth, no-deco time, and dive time simultaneously.
The display is clear and readable underwater. The menus are logical. It handles the core job well.
Where it falls short for me:
- • No GPS
- • No surface navigation features
- • Fitness/smartwatch integration is limited
- • The overall ecosystem doesn't match what Garmin has built
For pure diving, those gaps don't matter. For someone who wants one device that crosses over between diving, running, GPS navigation, and daily tracking, the i770R isn't that.
The Garmin Descent MK2 — Why I Want It
The Garmin Descent MK2 is a dive computer built inside what is essentially a premium GPS multisport watch. You get the full Garmin ecosystem — GPS tracking on the surface and underwater (via map), heart rate, fitness tracking, breadcrumb navigation back to the boat, and Garmin Connect integration.
For someone who already uses Garmin for other activities, or who wants surface GPS to mark entry points and navigate back, the MK2 is a different level of device.
The dive algorithm is solid. Air integration works with Garmin's own transmitters. The display is excellent. Build quality is what you'd expect from Garmin's top-tier hardware.
The price reflects all of this. It's a significant investment. But if you're consolidating devices and want one unit that does everything — it makes sense.
What Neither One Replaces: The Manual Backup
Here's the thing that doesn't get said enough: I always carry a backup hose and manual pressure gauge regardless of which wireless computer I'm using.
The reasons are simple:
- • Batteries can die mid-dive
- • Transmitters can lose signal
- • Electronic components can fail
Your tank pressure is not something you want to guess at. A manual submersible pressure gauge on a hose is $30–60 and takes up almost no space. It doesn't need batteries. It doesn't need a signal. It just works.
I check my wireless reading and my manual gauge together on every dive. They should match. If they don't, I know something's off before it becomes a problem.
Don't skip the backup because you have wireless. The backup exists for the moment the wireless fails — and that moment will eventually come.
Which One Should You Get?
Get the i770R if:
- • You want a capable, dedicated dive computer at a reasonable price point
- • You dive nitrox or trimix and need multi-gas support
- • You want wireless air integration without the Garmin price tag
Get the Garmin Descent MK2 if:
- • You want GPS, surface navigation, and a full multisport watch in one device
- • You're already in the Garmin ecosystem
- • Budget isn't the primary constraint
Whatever you get — add a manual backup gauge. That's not optional.
I'll be upgrading to the MK2 at some point. Until then, the i770R keeps doing its job. Both are honest tools. Neither replaces the discipline of watching your gauges and diving within your limits.