Huge air consumption even after +200 dives

[Jai Bar]

Also, you shouldnt really have a goal to reduce your sac to begin with.

Good sac rate is a result of good technique and efficiency in the water, so thats what you should focus on, and then sac rate will fall into place and you will reach your personal good sac rate. For everybody its a different number.

Normally, you are right, reducing SAC is not a goal and improves with experience.

However, OP appears to be experienced and with good technique from his description, and the problem, according to him, is that he works as a divemaster and probably concerned that he finishes air first. I can imagine some customers still with half tank full, pissed off that they cut the dive short because the DM runs out of air, or to have more reserve for one of those inexperienced divers that "suddenly" surprise you with a signal you they OOA...So I can understand the concern to improve sac in his case.

 

[nippurmagnum]

Get a 15 liter tank. Problem solved. And you'll probably relax knowing that you have plenty of gas, and by relaxing you'll consume less, and eventually you may be comfortable switching back to a smaller tank.

 

[Eric_K]

I'm your height, but only weigh 185 lbs with 16% body fat. I've had to work on my consumption my entire dive career. If indeed you are in shape (I lift weights and know that there are varying levels of effort by people), I'd suggest you work on your inhalation amount. You may be sucking down much more than your body needs, perhaps overcompensating for too much weight. In any case good luck!

 

[Diver-Drex]

Possibly stay a little shallower. Let the group go to the bottom and check stuff out. Staying higher in the water column will give you a better vantage point, you’ll be seen by the group easier and it will cut your air usage.

If you’re doing 15 meter dives, staying at 10m could help.

 

[KenE]

It appears you have worked out most of the common causes of high gas consumption. I am in much the same situation. The best advice I can give you is to try to remove stress as much as possible. My consumption went up when I was leading our group and back down when someone else led. So, I started working on the stress level when leading and brought my rate back to normal. Stress adds to breathing rate, thinking about breathing rate increases breathing rate. So, stop thinking about it and start enjoying leading groups. Find positives to focus on and not negatives, this will help reduce stress and consequently your breathing rate. I now practice breathing rates out of the water and stopped worrying about it underwater. My breathing rate dropped due to muscle memory and less stress. Have fun and keep diving!

 

[Tycksel]

Get a 15 liter tank. Problem solved. And you'll probably relax knowing that you have plenty of gas, and by relaxing you'll consume less, and eventually you may be comfortable switching back to a smaller tank.

I did few dives with 15L tank last winter, but it gave me maybe 5min more divetime. I only use 800g weight with 12L tank and with 15L tank I'm maybe 4-5kg overweighted.

I'm your height, but only weigh 185 lbs with 16% body fat. I've had to work on my consumption my entire dive career. If indeed you are in shape (I lift weights and know that there are varying levels of effort by people), I'd suggest you work on your inhalation amount. You may be sucking down much more than your body needs, perhaps overcompensating for too much weight. In any case good luck!

Yeah I noticed that even when my breathing rhythm is quite ok (around 4 sec in, 6-8 sec out), I feel that I suck lot of air during that 4sec inhale

It appears you have worked out most of the common causes of high gas consumption. I am in much the same situation. The best advice I can give you is to try to remove stress as much as possible. My consumption went up when I was leading our group and back down when someone else led. So, I started working on the stress level when leading and brought my rate back to normal. Stress adds to breathing rate, thinking about breathing rate increases breathing rate. So, stop thinking about it and start enjoying leading groups. Find positives to focus on and not negatives, this will help reduce stress and consequently your breathing rate. I now practice breathing rates out of the water and stopped worrying about it underwater. My breathing rate dropped due to muscle memory and less stress. Have fun and keep diving!

Yeah I tend to stress sometimes when I'm leading. Especially when visibility is poor, there's current and customers are not very experienced.

I've managed to drop my SAC rate to 19-20L/min in last 2 weeks, so maybe I have still hope

 

[SouthernSharktoothDiver]

Just a thought, but have you considered backmounted doubles? you could use a pair of standard AL-80's (12 L's to you non-Eaglelanders), and have plenty of air for your own use and if a customer needs to buddy breath. A bit bulkier, sure, but you're obviously strong with all the weight lifting, so I expect you could manage it well enough.

 

[Doc Harry]

250 dives?
You're still a beginner.
Keep diving.

 

[DreadnoughtNH]

I'm about your same height and weight. Like you, I've optimized my weighting, my technique, streamlining, and keep my SAC rate down. Trouble is, due to our size, we have proportionally larger muscles, larger lungs, and higher O2 consumption as a result. If you workout regularly -- particularly strength training -- it's even worse!

Simplest solution: bigger tank (100cf or 120cf). It will be proportional to your size. My friends like to joke that I carry a water heater on my back, but it's honestly not a hindrance given my size. I just make sure to bring a bungee or ratchet strap to keep it rolling around the boat since the larger diameters don't usually fit in the tank racks.

 

[scubadada]

I'm about your same height and weight. Like you, I've optimized my weighting, my technique, streamlining, and keep my SAC rate down. Trouble is, due to our size, we have proportionally larger muscles, larger lungs, and higher O2 consumption as a result. If you workout regularly -- particularly strength training -- it's even worse!

Simplest solution: bigger tank (100cf or 120cf). It will be proportional to your size. My friends like to joke that I carry a water heater on my back, but it's honestly not a hindrance given my size. I just make sure to bring a bungee or ratchet strap to keep it rolling around the boat since the larger diameters don't usually fit in the tank racks.

100s and 120s are 7.25 inches in diameter, same as an AL80. 117s and 133s are 8.0 inches in diameter.