Better SAC rate switching from Poseidon Xstream to Apeks

[BlueTrin]

Are you sure both regs very tuned the same/similarly?

I was training in mexico and my instructor had a very similar sac rate so after each dive we would come out with a very similar amount of gas left (adjusting for drills, exercises etc).

But for one dive I opened up my apekses (meaning increased how much gas they supply) and after the dive was over my instructor asked if i got bored and that's why i turned the dive? (when we came out he still had plenty of gas left, but i reached my thirds during the dive).

What ended up happening is because I opened up my regs and was breathing in more gas, my buoyancy breathing rhythm that i was used to got screwed up. So not only I was breathing in more gas, but I also had to breathe more often to keep the buoyancy where I wanted it to be, which led to a much higher sac rate. I actually have a video from that dive somewhere, and you can really see that my exhales produce an absurd amount of bubbles.




So maybe something similar happened to you? Poseidons delivering too much gas

Do you mean the Venturi lever?

I had a similar experience at first but then my sac reverted once I got used to the new setting.

Apeks venturi lever and air consumption

i had a go today at turning the Venturi lever. Usually I have it and the effort knob all turned to ‘-‘. Today I tried turning the lever all the way to ‘+’ and the turned the know a bit: this dramatically increased my air consumption. I thought that this would only make the regulator easier to...

scubaboard.com

 

[Bigbella]

my experience is the opposite with a better SAC rate on my Jetstream/Xstream vs Apeks/Deep6. The total WoB of an Xstream on inhale is lower than it is on an Apeks so any SAC rate change would have been based on your breathing pattern not the regulator itself. They do have a violent purge though!

That was also the experience of a friend who recently switched from Apeks to a well-tuned Jetstream MK3, which has nearly identical guts to the Xstream second stage . . .

 

[BRT]

We just got back from Q. Roo, Cozumel and Puerto Morelos. A friend who has dived with us there several years has had terrible air consumption. We got him big tanks and he still blew through them. I became suspicious that his reg breathed too easy, and got him an adjustable 2nd stage. We did about 40 tanks and the difference was astounding. Instead of hanging above us and heading up early he can now dive with us (with the big tanks). I have a Mexican spearfisherman friend who who only cracks his tank valve at first and slowly opens it up during the dive. He is convinced that harder breathing in helps him conserve air. Something does, cause he is good at it.

 

[clownfishsydney]

When I went from old, not very good regulators to new high performance ones, my air consumption went up. I always presumed this was because it was so much easier to breath and I was getting more air.

 

[Underwater Tourist]

Do you mean the Venturi lever?

I had a similar experience at first but then my sac reverted once I got used to the new setting.

Apeks venturi lever and air consumption

i had a go today at turning the Venturi lever. Usually I have it and the effort knob all turned to ‘-‘. Today I tried turning the lever all the way to ‘+’ and the turned the know a bit: this dramatically increased my air consumption. I thought that this would only make the regulator easier to...

scubaboard.com

I played both with venturi and the dialing knob, so not sure which one caused it specifically.
Given your experience, it must have been the former.

 

[Bazzathemammoth]

When I went from old, not very good regulators to new high performance ones, my air consumption went up. I always presumed this was because it was so much easier to breath and I was getting more air.

Me too. I got a Twinset and new regs earlier this year. My previous regs were bottom of the line unbalanced position regs and my new ones are some mk25 evos with g260 second stages.

The adjustable second has had more of an effect than I was expecting. I’ve been dialing it in, but at first I had it set to too hard to breathe, then too easy. Is now at a happy medium and I’ve gone from full Venturi to minimal.

Too hard to breathe was the worst as I had high air consumption and I think co2 buildup as well. Now it seems about right, I’m feeling good and I’m closer to my single tank RMV.

The settings seemed to make a big difference though. I’m normally ~15l/min on a single tank, and I’m now sitting at ~16l/m on the twins. Incorrect settings had me as high as 20l/m!!

I reckon being over weighted with the Twinset would explain the extra 1L/min too. My single tank weighting is pretty much bang on. I hadn’t heard of regs making this kind of difference before, and it’s good to read that I’m not the only one to experience this.

 

[Trypta]

Below is the breathing curve for the X-Stream and it certainly follows that. Apeks is a bit more balanced IIRC but you don't really perceive the exhale WoB the same way and it is well within the levels of top performing regulators. Any difference in SAC that I have been able to sort out is based mostly on the way the regulator breathes vs. the way your body breathes. I'm a musician so my body is used to very rapid inhales and the Poseidon almost requires that type of breathing, same with a double hose. "Sipping" on the regulator is something you can do with a properly tuned Poseidon but it will certainly try to open all the way as the venturi is quite strong.

View attachment 770624

Hi Tbone, im a newbie and i using a poseidon xstream. I realized that by sipping it, which my instructor recomended, did not give me any air, it has to be an effort to inhale the air from the 2nd stage. Would you share some tips on how to breathe efficiently on it? Does the 4secs inhale and 4secs exhale still works. I did that and my sac level is 2 bar

 

[Frogman82]

My poseidon xstream breathe smooth regardless of wheter I sip or breathe heavy. Maybe you should get the ip checked and the regs tuned. I have it set to 120 psi which is just a tad lower then the factory spec of 123.

 

[admikar]

Hi Tbone, im a newbie and i using a poseidon xstream. I realized that by sipping it, which my instructor recomended, did not give me any air, it has to be an effort to inhale the air from the 2nd stage. Would you share some tips on how to breathe efficiently on it? Does the 4secs inhale and 4secs exhale still works. I did that and my sac level is 2 bar

Best breathing pattern for you is whatever works for you. Dot skip breathe, but whatever else works works.
Can you try some other reg and see if you can notice any difference in how it breathes?
As for your SAC level, 2 bar is meaningless unless we know with what tank you have that. Best unit is either l/m or cfm.

 

[Trypta]

My poseidon xstream breathe smooth regardless of wheter I sip or breathe heavy. Maybe you should get the ip checked and the regs tuned. I have it set to 120 psi which is just a tad lower then the factory spec of 123.

I will have it checked, thank u for the feedback