Mandatory Gas Time Alarm at beginning of the dive
-
@hhouter damn. I got a email from Suunto with standard answers. Check tank check pod i all did that. It is a wide problem under more Nautic users. Monday i go diving again if the problem is coming back i go send the data to Suunto and let you guys know
-
MartinPadiPro said:
@hhouter damn. I got a email from Suunto with standard answers. Check tank check pod i all did that. It is a wide problem under more Nautic users. Monday i go diving again if the problem is coming back i go send the data to Suunto and let you guys know
Dear Martin,
Thank you for contacting Suunto Support and for sharing the detailed information about the issue you experienced during your dives.
We understand your concern, especially when the dive computer shows a low gas alarm despite having sufficient tank pressure. We will be happy to help you investigate this further.
When a Suunto dive computer triggers an unexpected low gas alarm or the Gas Time value resets despite having enough tank pressure, it is usually related to one of the following factors:
- Tank Size Configuration
Gas time is calculated dynamically based on your current depth, tank pressure, and breathing rate (Surface Air Consumption / SAC).
Please check:
Go to Gases > Edit Gas
Confirm that the Tank Size (Volume) is correctly configured
If the tank size is incorrect or missing, the gas time calculation may become inaccurate.
- Initial SAC Calculation Phase
During the first 5–10 minutes of a dive, the algorithm calculates your breathing rate. A higher breathing rate or sudden depth changes during descent may temporarily reduce the estimated gas time, which can trigger an alarm before the calculation stabilizes.
- Gas Time / Pressure Alarm Settings
Please verify your alarm settings:
Go to Dive Settings > Alarms
Check your configured pressure and remaining gas time alarm thresholds
The default mandatory tank pressure alarm is set to 50 bar, but custom alarm values may affect when notifications appear.
- Temporary Tank POD Signal Reconnection
If the wireless connection between the Tank POD and dive computer is interrupted temporarily, the pressure reading may briefly disappear and then update once the connection is restored. This recalculation can appear as a sudden reset of the Gas Time value.
Before your next dive, we recommend checking the following:
Connect both dive computers to the Suunto App and ensure they have the latest firmware installed.
Confirm the Tank POD is correctly paired and the pressure reading matches your mechanical pressure gauge before entering the water.
Ensure the Tank POD battery and connection are functioning correctly.
As a standard safety precaution, please continue relying on your mechanical pressure gauge if any wireless pressure readings appear inconsistent.
After your next dive, if the issue occurs again, please sync both devices with the Suunto App and provide us with:
Dive computer model(s)
Firmware version(s)
Approximate dive time when the alarm occurred
Any screenshots or dive logs available
We will review the information and assist you further.
Thank you for your cooperation.
Best regards,
Zack
Suunto Support Team -
https://photos.app.goo.gl/1o43GWsetjia3SfN9
https://photos.app.goo.gl/zhhZfuxBsEteLWo1A
This are mine screenshots
-
During the first 5–10 minutes of a dive, the algorithm calculates your breathing rate. A higher breathing rate or sudden depth changes during descent may temporarily reduce the estimated gas time, which can trigger an alarm before the calculation stabilizes.
Interesting… but that is the issue with the full tank and in descent, this alarm in the beginning of the dive should never pop-up.
I have also submitted them the logs and model / Serial numbers etc… but didn’t hear back from them yet. The alarm in my last dive at 6m was not scary… the one I got at 33 meter was !!! I simply hope that I never get an alarm in the beginning of a dive which is relevant because now treat them all as irrelevant.
-
@MartinPadiPro I have two buddies who also have a Nautic. This issue was seen by both, but they don’t bother to submit to Suunto. So it is definitively not a standalone problem…
-
@MartinPadiPro Sounds like a bot, all those answers don’t make sense for the described situation. I hope Suunto is taking that case serious, after algorithm lock and depth sensor failures it could be the next fiasco pushing customers to Garmin or Shearwater.
Thats a shame, when I started diving the question was just which Suunto to choose as a dive computer. Everyone had Cobras, Vypers and then Zoops, but it had to be a Suunto -
@VoiGAS On my first dives with the Nautic I was wearing my EON Core on my other arm to compare RGBM vs buhlman. So the first dives and my first Mandatory Gas’s Time Alarm were recorded with two Suunto dive computers on one POD. The Core was flawless and didn’t have any interruptions, but the Nautic gave the error. This is why I think there is a bug in the algorithm calculation of the Nautic.Due to the fact this was my first Mandator Gas Time Alarm, I ascended immediately after the alarm. Both logs were sent to Suunto support. See both logs, below:
-
@hhouter little bit offtopic, but I am really interested in your experience with the two algorithms. Maybe you like to share them here: https://forum.suunto.com/topic/15559/bühlmann-vs.-rgbm/10
-
@VoiGAS Yes, will respond with my findings there.
-
A question to make things clear. You only get this alarm on the Nautic, not the other air integrated computers? The problem is with the Tank POD not the older transmitter?
-
@ccrhenrik Correct. Two computers connected to same Tank POD. The EON Core does not give me the error, the Nautic does. See screenshots of same dive in post above. The tank pressure graph in both computers are equal and do not indicate any loss of pressure, see screenprints below.
So my conclusion is that it is not a tank pod error or inteference of a flashlight as the EON didn’t give me the error and functioned correctly. There should be a bug in the Nautic as it indicates the 5 Minutes Mandatory gas time alarm with full tank in certain situations in the beginning of the dive.
See both logs;
-
@hhouter made two dives today.
No gas alarms this time.
Everything went well. -
@MartinPadiPro Yes, but let me guarantee you that you will encounter the same issue soon (if Suunto doesn’t fix the issue in an update). Between my first and second time I had 5 months diving without issues, between second and third, 1 month.
-
@hhouter I hope they will fix it soon. Tomorrow i will go diving again. Fingers crossed
-
A friend diving with the Nautic received a mandatory gas time alarm in the beginning of a dive today 29/07/2026.
Suunto please do something about this. This is not an isolated issue or a faulty Nautic that needs to be sent-in for service, it is a issue in the current firmware…!!
See below the response from support, this cannot be true. Triggering an alarm is a serious situation and cannot be left up to the divers interpretation to wait for the stabilization of the calculation.
Initial SAC Calculation Phase
During the first 5–10 minutes of a dive, the algorithm calculates your breathing rate. A higher breathing rate or sudden depth changes during descent may temporarily reduce the estimated gas time, which can trigger an alarm before the calculation stabilizes. -
For me, the real concern is not simply that the gas-time value is briefly wrong.
As the screenshots show, divers started ascending after the mandatory red alarm because they understandably believed they might have a serious gas problem. An experienced diver may be able to verify the actual gas situation underwater, but a less experienced diver could panic and make a dangerous decision.
If Suunto knows that the gas-time calculation may not yet be reliable during the first minutes of a dive, then it should not be able to trigger a mandatory critical alarm at that stage.
There is also the risk of people losing trust in the warning after several false alarms and then hesitating when a real one occurs.
I will report this through ICSMS for the European market tomorrow so that it can be assessed independently. Divers in the United States may also want to report the issue through SaferProducts.gov, the reporting system of the US Consumer Product Safety Commission.
-
See also the facebook Suunto Nautic group. More people are impacted.
-
Had the same thing happening a month back. Also when checking the graphic, it shows a very high gas consumption during the same time.
I exported the raw JSON from the app and used AI (Claude) to help me dig through the samples. Here’s what it explained:
Suunto Nautic on 2.49.32, Tank POD, 12 L, alarm at 02’07.6 at 5 m.
The pressure data is clean — 10 s samples, ~0.01 bar resolution, completely smooth through the alarm (202.03 → 201.42 → 200.86 → 200.77 → 200.17 bar). No dropout, no reconnect step. Consistent with what @hhouter found running an EON Core on the same POD.
But the consumption line in the app isn’t derived from that pressure. The Nautic logs a separate
Ventilationfield per cylinder, in m³/s, and calculates remainingGasTimefrom it. Here’s what it does around the alarm:110.2 s Ventilation 0.000421 (25.3 l/min) GasTime 2956 s 119.9 s null null 127.6 s null null <- alarm 129.9 s 0.001667 (100.0 l/min) 0 s 137.7 s 0.001562 (93.7 l/min) 755 s 209.9 s 0.000059 (3.5 l/min) 6000 s (capped)Two null samples, then it re-initialises and its first output is 100 l/min. That puts remaining gas time at literally zero seconds, which fires the alarm. Eighty seconds later it’s back at the ceiling.
The field is off outside the glitch too: it reports 3.2 l/min at the point where my pressure was dropping fastest of the whole dive, and integrated over the dive it’s 40% below the gas I actually used.
So “the algorithm is still calculating your breathing rate” doesn’t hold up. A stabilising average converges — it doesn’t go null and restart at a physiologically impossible value. And an estimator in an invalid state shouldn’t be able to trigger a mandatory alarm at all.
If you want to check your own log, export the JSON and look for
Ventilation: nullmid-dive immediately followed by a huge value andGasTime: 0. Happy to share the script I used. -
Hello! It looks like you're interested in this conversation, but you don't have an account yet.
Getting fed up of having to scroll through the same posts each visit? When you register for an account, you'll always come back to exactly where you were before, and choose to be notified of new replies (either via email, or push notification). You'll also be able to save bookmarks and upvote posts to show your appreciation to other community members.
With your input, this post could be even better 💗
Register Login