SAC worse with new reg

[Karlstumke]

Hmmm... This could explain your low consumption. Are you sure you are using the correct tank size? For example in several parts of the world 11.1lt tanks are commonly refereed to us 12lt. In your case this particular misconception would make your measured SAC worst than your real one - not better as in your case, but still are you sure you are using the correct tank size? What matters is not what people call them but the number that is written on their neck.

Sorry but without knowing much about you (experience, amount of dives, training, comfort underwater, equipment, diving conditions etc etc) it is difficult (but for sure not impossible) to have such low gas consumption. So I'm looking for sources of error.

Now about the increase in your SAC with your new reg. There are a lot of factors that can impact SAC. Heart rate is one of them - but translating one to the other is not as straight forward, I think.

In my case, for relaxed wetsuit dives I usually have a SAC of about ~12lt/min (after about 450 dives over 8 years). With drysuit I have much less experience (about 50 dives over 3 winters that I use drysuit) hence my comfort level is much lower and my SAC rices easily to about 15lt/min. But this is a quite different setup (drysuit, more lead, heavier fins, cold water, etc).

Another thing that might be affecting your SAC is that maybe you worry too much about it (or other things). Maybe you don't trust yet your new reg setup? Maybe you are overthinking about it? Maybe something else? Worrying about things (including gas consumption) during the dive definetly increases SAC.

For a so noticable increase in your SAC I would look for this kind of factors. A small mistunning, or breathing effort difference shouldn't cause so drastic SAC increase.

That's my 2c as always. I let other, more experienced divers further comment.

All the best....

Actully the garmin is configured to 11.1l metric. The VALUE is academic, Whether its 9/10/11. What i am asking is on the comparison..i.e. The relativity of the numbers to each other. Anyway i will try in two weeks and then see...

 

[grantctobin]

Any ideas

Unless the reg is free flowing, it is very unlikely that switching between two appropriately tuned, balanced second stages will be the cause of change in your SAC rate, and especially not 30+% worse. I’m with @stepfen on this one.

 

[Karlstumke]

Unless the reg is free flowing, it is very unlikely that switching between two appropriately tuned, balanced second stages will be the cause of change in your SAC rate, and especially not 30+% worse. I’m with @stepfen on this one.

Over next few days i could manually work. Out SAC and see if it correlates with Garmin calculation. I see thst if you use 80 imperial it defaults yo 12l air although i input 11.1 manually each time