When you start diving one of the biggest obsessions is to try to use as little air as possible on each dive. It is normal for the novice divers to be concerned about being underwater as much as possible so as not to force their more experienced partner to end the dive with 120 bars. Although this obsession is more common in the Open Water Divers, there are also divers with many dives who seek to optimize the use of air each time they dive. Follow these seven tips and you will get to stay under water more and more time.

Improve the position of your body
By achieving neutral buoyancy you will have less resistance to water and the effort you will have to make to move will be less, therefore using less air.
Choose your weights accordingly
If you take more weight than it suits you, it will be impossible to maintain a good buoyancy control and you will spend more air. The usual thing is to use around 10% of your weight as ballast weight (I would say even less), but the best thing is that you try different weights and configurations, try putting it on the vest and on the belt… dive with different weights and use the one you are more comfortable and be more agile. Use your log book to note down the weights and how you are feeling underwater, it will help a lot.
Use a regulator that you feel comfortable with
Having a good regulator with which you breathe easily and with which you do not have to make an effort to get the air will keep you more relaxed and, therefore, you will use less air. In addition, remember to keep both the octopus and the manometer attached to your body, it will improve your body position and you’ll need less effort to move.
Breathe deeply and slowly
It is important that you expel from your lungs as much air as possible in each exhalation to get new fresh air in your lungs, for this it is essential that you breathe slowly and deeply. Thus you will be much more relaxed, your muscles and brain will be better nourished and you will have a better predisposition to enjoy the immersion.
Dive
It seems obvious but many Open Water Divers swim more than they dive, using their arms to move underwater. Get good buoyancy, just use your fins and keep your arms under the chest or belly, you will save lots of air.

Just relax
This is the most important factor to use less air. Although it is difficult in the first dives of everyone of us, time and experience will allow you to relax more and more and you will see how the air consumption is getting smaller. If you enjoy diving you will end up relaxing and using very little air.
Do not get obsessed with air consumption
As the runners who are looking at their GPS watches every 2 minutes to check their heart makes heart rate increase, if you are constantly looking at the manometer to see how quickly you consume the air you will end up with it right away and you will not enjoy the dive. If you quit thinking with the air you use you will finally relax yourself, breathe deeply and slowly, your muscles and brain will receive more oxygen, you will adopt a more comfortable position to dive and you will end up spending more time underwater. Look at the gauge, of course, but is enough to check every 3-4 minutes. Keep in mind that you are diving to see the environment, not the pressure gauge.
Do not worry if you spend less time than you would like or if your buddy has to come up with half-full tank. Nobody was born knowing how to dive and we all «drank» the bottle in the first dives. Be patient, relax and enjoy breathing underwater, you are privileged human being.