Conventional SCUBA diving uses an open circuit breathing apparatus, which means that the air we inhale into our lungs from the tank is dispelled through the regulator in our mouth into the water as we exhale. The problem with open circuit breathing is that it wastes precious gas. Out of the air we fill into our scuba tanks, 80% of it is Nitrogen and other gases, and only 20% of the air is Oxygen. Out of that 20% of Oxygen in our dive tanks, our lungs only absorb a quarter of the Oxygen contained in the air for each lungful we take, which means divers exhale 3/4^ths of the total oxygen available to them each dive.  This means despite carrying all that air in our tanks, we are only really consuming a tiny fraction approximately 5% of the total air (oxygen) and exhaling everything else.

A Rebreather also known as a Closed Circuit Breathing Apparatus or CCUBA or a CCR (Closed Circuit Rebreather), allows a diver to breathe the exhaled air, again and again while constantly removing the CO2 while replenishing Oxygen into the system as necessary.  Oxygen or a Gas Mix, is fed electronically or using a demand valve into a closed circuit system. The air goes into the Diver’s lungs and the Carbon Dioxide rich air is breathed out into a separate one -way-valve path into a counter lung which is a bag that expands and contracts like a lung that stores exhaled air, allowing the air in the loop to remain the same. The air from the counterlung is then pulled into a Carbon Dioxide Scrubber, which is a container filled with a CO2 absorbing Chemical usually sodium hydroxide (Sofnolime). The carbon dioxide (gas) reacts with sodium hydroxide and calcium hydroxide to form calcium carbonate (solid).  The Oxygen or Gas mix that is released from the tank into the loop is controlled by oxygen sensors  that monitor the partial pressure of oxygen in the breathing loop and send this information to a microprocessor that controls the oxygen-delivery system.

Advantages of a Rebreather

- A Longer Bottom Time A Closed Circuit diver doesn’t need to worry about running out of gas they are is limited only by decompression. This too can be minimized by selecting a partial pressure of oxygen which virtually gives the diver limitless bottom times in 60 feet or less of water.

- No Bubbles A  Fully closed circuit breathing apparatus, discharges no bubbles, making it ideal for underwater photographers/videographers  who would otherwise scare away marine life with the constant stream of bubbles. Rebreathers are also used by the Military because of this; they can stealthy move underwater without fear of detection at the surface by the giveaway stream of bubbles.

- Gas Efficiency As the oxygen in the system is re-circulated in the loop, a diver may utilize up to 99% of the Oxygen in the system as opposed to an open circuit system where 20% of the Oxygen is absorbed by the Divers lungs.  This creates gas efficiency, with a tank the size of a regular air tank of oxygen lasting ages longer before needing to be changed, limited only by the scrubber.

- Deep Diving A closed circuit rebreather helps in deep diving as a helium system could be easily added to the circuit to eliminate narcosis. The tanks needed for a deep dive are not as many with a rebreather as needed for an open circuit system, allowing the diver greater mobility.

Are you ready to switch yet? Do keep in mind that everything isn’t all perfect with a rebreather. They are extremely expensive pieces of Scuba diving equipment, and require chemical cartridges changes, and proper maintenance. There is more that can go wrong with the complexity of the rebreather, and the diver must be aware of scrubbers failing or reaching absorption capacity, or Oxygen toxicity if the controllers fail.

*Photo credits: photos by tiswango, amell, on flickr.

Even though Regulator recovery and clearing is one of the most basic things taught to a diver during his open water certification course, it is still a crucial skill that several  divers are reluctant to learn or practice after their certification courses.  Regulator mouthpieces get knocked out of divers’ mouths all the time, and can easily get snagged on BCD’s. In our certification courses we learn to recover our scuba regulators while kneeling on a steady platform such as the sea bed or the bottom of a swimming pool, which is why it is important to practice recovery where you may not be able to steady yourself.

The important things to remember while recovering your regulator is :

Don’t Panic – calmly try and locate your regulator mouthpiece using the practiced methods

Exhale continuously when you lose your second stage, to prevent lung over expansion injuries. Avoid holding your breath.

Sweep Method
The sweep method is the most commonly used technique to recover a second stage regulator. It involves  the diver leaning towards the right to let gravity move the second stage away from you and then stretching out your right hand in front of you and  making a sweeping arc,  back and right towards the bottom of your scuba tank so that the regulator hose should now be in front of you, and then bringing your arm forward catching the rouge regulator.  You then bring the regulator to your mouth purging the piece first before resuming normal breathing. The whole process takes less than a few seconds and can be repeated a couple of time if you are unsuccessful at first. Always remember to continuously breathe out through the process to prevent your lungs from over expansion, should you be unconsciously ascending while looking for your dive regulator.

Over-The-Shoulder Reach Technique
The Over-the-shoulder reach technique is one of the more effective techniques for lost scuba regulator recovery. Lean towards the right turning your neck to the right while reaching  back with your right hand until you feel the first stage of your regulator while at the same time lifting the bottom of your tank with your left hand so you can see the first stage. Then following the hose from the first stage with your right hands thumb and forefinger bring it forward so you can find the second stage and retrieve it. Many find this technique a little tricky and prefer the sweep method, however with a little bit of practice, the over-the-shoulder retrieval is more reliable.

Secondary Regulator
What if you cannot retrieve your regulator using both the sweep method or over the shoulder reach? Don’t panic, use your spare secondary regulator that should be clipped onto the front of your BCD, unclip it and begin breathing normally. Then calmly try to locate your main second stage once again.

Get your Buddy to Assist
Sometimes it helps to signal your buddy to help you spot your missing regulator, as it could be snagged in your BCD belts.  Use your spare regulator while your dive buddy assists you with retrieval. Some divers comfortable with removing their BCD’s while maintaining buoyancy, do so to free their tangled hoses. Always remember to have your buddy standing by to perform buddy breathing if you ever attempt to try this.

Clearing
Clearing your regulator is as simple as exhaling sharply into it. All the water will be expelled from the regulators exhaust valve. The other method to clear your mouthpiece is to use the purge valve. A quick two bursts of the purge valve immediately before putting it into your mouth should remove any water or debris from the chamber.  Or alternately depress the purge valve while it is in your mouth blocking the mouth piece with your tongue to prevent the burst of air into your mouth. Be careful to release the purge valve once you resume inhaling to prevent over filling of the lungs.

Scuba Divers should practice all of these methods in a controlled environment on a regular basis, so that they remain calm when the situation may occur. Use the method you are most comfortable with using and ensure you practice more than just one.

When you invest a good amount of money into owning your own Scuba Gear & Equipment, you have got to maintain and take good care of it. Your safety and well being are dependent on the Scuba gear you use dive after dive and nothing shortens the life of your gear like neglecting it. As your primary way of breathing underwater and essentially your lifeline, Scuba regulators are one of the most important pieces of equipment used in diving. Taking proper care and cleaning your diving regulator regularly is crucial to it’s maintenance.  Follow these few steps and make them a routine habit after every dive to keep your gear in good condition, making it well worth the cost and your efforts.

Here are a few steps to taking good care of your Scuba regulator-

1. Taking your regulator off your Scuba tank, you first want to make sure to dry the dustcap by blowing the water off with the help of the air from the tank or with a dry towel. The idea is to keep the first stage of the regulator absolutely dry, so go ahead and blow some air from your tank into the first stage as well to dry it properly before sealing it tightly with the dustcap.

2. Rinsing your regulator properly is the most important step to maintaining it. Regardless of whether you have been diving in salt water or fresh water, see that the first thing you rinse off with fresh water is the regulator if not any of your other equipment.

3. Soak your regulator in warm (not hot) water to dissolve any dried salt crystals or other deposits that may have accumulated in the interior. While the regulator is soaking it’s a good idea to slosh it around and push any buttons or work the levers underwater to loosen any stubborn particles. However, be careful not to push the purge as you don’t want water to flow through the hose and back into the interior of the first stage assembly.

4. Run a stream of fresh water through any open ports and chambers to get rid of remaining particles, if any. Take off the yoke screw and rinse both the yoke and screw threads with the running water, carefully keeping the dustcap secured over the first stage.

5. Allow your dive regulator to dry properly (not in direct sunlight to protect the rubber parts) before storing it in a cool dry place with all the hoses neatly arranged and not tangled.

6. Get your regulator professionally serviced. Most manufacturers recommend a servicing by a trained technician annually. If you use your regulator extensively or commercially, it should be serviced every six months or every 50 dives.

* Pictured above – Mares Proton 42 Metal She Dives Regulator from LeisurePro.com

Have you ever been on a dive where you look out not too far away into the distance and see a massive shoal of barracuda’s, jacks, fusiliers or other variety of fish give you that feeling of being small and insignificant in their world? Well, that’s exactly the kind of feeling some fish off the coast of North Sulawesi would have had when they saw a slightly different although extremely large shoal of a completely different species in August this year! 2861 divers went for a 31 minute dive simultaneously off the North Sulawesi capital Manado to earn themselves a new Guinness book record. A press release posted by Hobie on DiveBuddy.com quoted

“We have just smashed a world record today. It gives us pride as we can prove our country is a strong maritime nation,” Fisheries and Maritime Affairs Minister Freddy Numberi said after the mass dive.

The number of participants in Manado set a new world record of “most people scuba diving simultaneously”, breaking the previous mark of 979 set in Maldives in 2006.

North Sulawesi Governor Sinjo Sarundayang, Gorontalo Governor Fadel Muhammad, deputy Navy chief Vice Adm. Moekhlas Sidik and 51 foreigners were among the participants of the record breaking dive, which was held as part of the Sail Bunaken festival.

This couldn’t have been an easy feet and just considering the logistics of arranging such a dive would be a nightmare for even the most seasoned dive operators. A feat of this sort would involve 2,861 sets of masks, air tanks, , regulators, wetsuits and no less than 5722 fins! That is one large dive group to say the least.

If only we had some underwater images of what 2861 divers in the water looked like I’m sure it’s an image the fish of that region won’t forget. For each one of those divers, it would have been something fresh for the long book which most other divers couldn’t claim to have seen on their dives.

Photos by: The Daily Telegraph Australia & iTelegraph uk

Buying diving gear and equipment especially diving regulators and octopuses, can be quite daunting with the endless array of features, types and the technical terminology that that gets thrown into the equation when you are in the market to buy one.   A good place to start first is understanding ‘How a Scuba Diving Regulator Works’ and understanding what the first and second stage in diving regulators are, then looking at the types and differences between them as we’ll point out here.

Balanced Vs Unbalanced Vs Overbalanced Regulators
These terms refer to the parts used in the first stage of regulators and mean the following-
-          An unbalanced regulator uses fewer parts. As a result it sacrifices a bit performance at lower tank pressures and at deeper depths. It’s mainly suitable for very basic diving.
-          A balanced regulator uses more parts in the first stage of the regulator to ensure that it delivers the same amount of air at all pressures and depths. So the performance of such regulators is consistent at all times of the dive and in either shallow or deep waters.
-          An overbalanced diving regulator incorporates a technology that makes breathing easier as you go deeper. These type of first stage regulators is mostly seen in the top ranges.

Piston Vs Diaphragm Regulators
Again in the first stage of regulators for the same function of lowering pressure from the tank, a diaphragm or piston is used. Both types perform more or less the same and both perfectly great and very reliable for recreational diving. The only difference between the two is-
-          Piston regulators are basic and simple have a slight performance edge at depths. They cannot be overbalanced.
-          Diaphragm regulators are a little more resistant to cold and water with particles like silt, sand or salt as the internal parts aren’t directly exposed to the water like in the piston type.
The differences are negligible in both types and aren’t really a serious consideration when choosing a diving regulator.

DIN Vs Yoke/ A-Clamp
These are the two different types of fitting for attaching your scuba diving regulator to your tank.
-          DIN which stands for Deutsches Institut für Normung is a fitting that screws directly into the tank. It’s more commonly used in Europe.
-          A Yoke fitting screws over the tank. It’s also called A-clamp and is most popular in the UK.
Both types of fittings are reliable and used commonly. If you choose to go with a DIN fitting you can buy a DIN to yoke style converter which will give you the flexibility of using either one whichever is more convenient at the time.

High Pressure and Low Pressure Ports
The first stage of scuba diving regulators has ports which connect other parts of the regulator like an octopus, inflator hose, pressure gauges, dive computers (sometimes wireless) and any extras. These can be high pressure or low pressure ports.
-          Low pressure ports are used to connect only low pressure items, via a hose, such as the second your alternate breathing source and your Buoyancy Compensator inflator.
-          The high pressure ports connect high pressure items such as your analog pressure gauge or dive computer.
It is useful to choose a regulator with multiple high pressure ports should you wish to add on any extras in the future.

Nitrox Compatible
Another aspect to consider when buying a Scuba regulator is whether it is Nitrox compatible should you choose to dive Nitrox later.

For more on How to Choose a Diving Regulator, here’s a video demonstration by one of our professionals at Leisurepro showing you the differences and types of regulators you just read about-

*pictured above- Mares Abyss 22 Extreme Regulator

When learning about diving you are shown the diving equipment and how to use it, but often left unexplained is exactly how each component in you dive kit works. But this knowledge comes handy when you are looking to buy your own dive gear, as it’s not the cheapest purchase and you’d want to make an informed decision to suit your needs. Our Scuba Gear Articles are aimed at doing just that, helping you with all the information you need to Buy Scuba Diving Gear & Equipment.

The most important and key piece of any divers equipment is the Regulator. A diving regulator is the lifeline between the diver and his air source (Scuba tank) underwater. This breathing apparatus that is the regulator and tank, are the only means of a person breathing underwater. In other words they are what makes SCUBA Diving (which stands for Self Contained Underwater Breathing Apparatus) possible at all.

The primary function of a scuba regulator is to decrease the high pressure under which the air in your dive tank is stored, to a much more reduced and safer pressure level which you can breathe at any depth. For this purpose Scuba diving regulators work in two stages-

First stage: Air is compressed and stored in the tank under high pressure, about 3000psi. In order to reduce this pressure, the first stage is a valve or piston that lowers the pressure to about 140psi to let air into the hose. The valve opens to let some air into the hose and then closes again. A regulator compensates the pressure as it decreases in the tank when air is used and as the diver changes depth which causes change the ambient water pressure.

Second stage: The second stage of a scuba regulator is basically the part that goes in your mouth and delivers air upon demand. It contains a mechanism that reduces the intermediate pressure in the hose coming from the first stage to the surrounding water pressure making it comfortable and easy to breathe. Like in the first stage, the second stage also contains a piston or diaphragm construction which starts and stops the airflow. The mouthpiece, an exhaust valve and an emergency purge valve/button are all parts of the second stage. The exhaust valve lets the air escape into the water when you exhale. It is a one way valve and does not let water in. When the purge button is pushed, it forces air to flow continuously into the second stage chamber forcing any water out of the mouthpiece through the exhaust valve.

Diving regulators also come in different types using slightly different mechanisms. They can be balanced or unbalanced, piston or diaphragm and use a yoke or DIN clamp we take a look at these terms and regulators in ‘How to Choose a Diving Regulator’.