Dive Computer Reviews – Understanding The Terms Used

Cressi Archimede 2 Dive Computer ReviewNowadays, dive computers have replaced the use of dive tables. Dive tables would work only if precise monitoring is practised. A dive computer reduces risk while allowing you to maximize your bottom time.

A dive computer is an electronic instrument with a pressure sensor, electronic circuitry, a battery and a display. A programmed computer inside the instrument uses pressure and time information to continuously calculate the uptake of nitrogen by various compartments that have different half-times.

Names such as the Cressi Leonardo scuba dive computer, Aeris dive computer, Oceanic dive computers and Suunto dive computers will come to mind. Additional well-known brands will include NiTek Duo and NiTek Triodive computer, Mares Nemo Sport dive computer as well as Mares Nemo air dive computer.

With a proliferation of dive computers on the market, you’ll hear about the modified Haldane ratio, half-times, tissue compartments, Workman M-values, Buhlmann M-values, and algorithms in most of the computer literature. To make some sense of these terms, it pays to understand some basic decompression theory. You may wish to pick up “The Certified Diver’s Handbook: The Complete Guide to Your Own Underwater Adventures
” by Clay Coleman for more details.

As mentioned earlier, a dive computer continuously calculates the uptake of nitrogen by various compartments that have different half-times. A half-time is the length of time required for a mathematical model (compartment) to increase or decrease its gas absorption or elimination by one-half.

A compartment, which resembles, but does not duplicate body tissues, is completely saturated or desaturated in six half-times. When the absorption by any one of a computers compartments reaches a predetermined level, the device indicates that you are approaching the time limit after which a direct ascent to the surface will no longer be possible.

On reaching the time limit, the computer indicates a minimum depth – a ceiling – that you cannot exceed during ascent. You risk decompression sickness unless you wait till your dive computer indicates that sufficient outgassing has occurred to allow you to continue your descent.

A dive computer provides extremely accurate time and depth information. Other common features are a low-battery warning, a rapid-ascent warning, a dive log mode, a dive-planning mode, and information about flying after diving.

For more information on the type of dive computers available on the market, be sure to click here for dive computer reviews.

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Scuba Regulator Reviews – The Best Scuba Regulators For Different Dives

In the previous blog post on choosing the best scuba regulators, some tips have already been provided on the best scuba regulators for shore dives. Read on for more additional tips on how to find the best scuba regulators for your personal needs.

Second Stage

The second stage of a regulator goes into your mouth. It is at the end of the low-pressure hose that contains the air at intermediate pressure delivered by the first stage. As the diver inhales, a diaphragm is bowed, which presses a lever connected to a valve. The harder the driver inhales, the more the lever is depressed, allowing an increased flow of air.

When the diver exhales, the exhaled air pushes through a simple one-way flap valve and escapes without allowing water to enter. The exhaled air is funneled through a tee beneath the mouthpiece to disperse the bubbles. The purge button on the regulator pushes the lever that allows air to flow. This lever is the same lever that is pushed by the diaphragm when you inhale.

To deliver air as easily and efficiently as possible, manufacturers have come up with various diver-controlled means by which divers can fine-tune the flow of air. The result is the emergence of devices with names such as air assist, vanes and venturi effect devices.

Most modern regulators have a tendency to free-flow at the surface if the second stage is in the water and if the mouthpiece is not in the diver’s mouth and is higher than the purge button. This happens because the second stage is so finely tuned that the difference in pressure of only a few centimetres of water is enough to start the delivery of air. To stop the free flow, just turn the second stage over so that the mouthpiece is pointed downward.


Ports not just deliver air to your mouth. They also deliver air to other devices such as the inflator for a buoyancy conpensator, an alternate air source, or a dry suit. All regulators provide either high-pressure and low-pressure ports. Regulators typically have one or two high-pressure and three to four low-pressure ports. The ports are clearly marked to prevent hose mistakes.

Your submersible pressure gauge is connected to the high-pressure HP port via a high-pressure hose. The three low-pressure LP ports are used with low-pressure hoses for the primary second stage of your regulator (the one that you breathe through), the secondary or alternate (octopus) second stage, and the BC inflator.

If you still need to inflate your dry suit, you will likely need an additional LP port. You may therefore need to purchase a more expensive regulator. The more expensive regulators typically provide more ports, both HP and LP, allowing you to more easily configure your gear.

Watch the video below on how to assemble your scuba regulator:

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A good scuba regulator lets you breathe easily over a wide range of tank pressures, which implies a balanced first stage. When shopping for a scuba regulator, choose a widely used regulator which can be easily serviced by facilities anywhere you happen to be and that uses readily available parts.

The type of diving you plan to do will have an influence on your selection. If you plan to do most of your diving from shore, you should avoid a pilot-valve second stage which is easily badly affected by sand and dirt. Regulators with diaphragm first stages are a better choice if most of your diving is from shore.

If you do not have a scuba tank, consider purchasing the tank and regulator at the same time so that you can match the fittings of the regulator and the cylinder valve. If you dive in water that is near freezing, be sure to selct an environmentally shielded regulator. Take note also that enriched-air nitrox and mixed gases require specially cleaned and dedicated regulators.


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The Best Scuba Regulators – Choosing One For Your Needs

Reviews On Scuba RegulatorsReading reviews on scuba regulators is probably one of the best ways to choose a scuba regulator which suits your needs and the type of dive you plan to make. Before you rush out to select from top of the line scuba regulators, you must first understand the type of scuba regulators that are available, as well as the parts which form a scuba regulator.

The air in your scuba tank is stored under extremely high pressure up to the maximum of 3000 pounds per square inch. When we dive underwater, we need to be able to breathe effortlessly on demand. This is achieved by the scuba regulator, the function of which is to reduce high-pressure air to a breathable level.

The scuba regulator is therefore our life support. It enables us to breathe effortlessly regardless of the depth by delivering air at a pressure that matches the surrounding water pressure. This pressure changes as we ascend or descend.

The scuba regulator is a simple device which is rather durable and dependable. Every scuba regulator marketed by established manufacturers is of adequate design and workmanship to allow recreational diving to depths of 45 metres.

This being said, scuba regulators may still very in prices ranging between US$250 to US$1500. So how do you choose one which suits your needs?

All scuba regulators deal with pressure in three stages:

1. High Pressure

High-pressure air is reduced to intermediate or low pressure.

2. Intermediate Or Low Pressure

Air that is reduced to moderate pressure can be easily controlled for effortless breathing. This pressure is maintained constantly between the first and second stages of the regulator regardless of the diver’s depth.

3. Ambient Pressure

This refers to the pressure surrounding the diver at any given time.

The scuba regulator comprises two stages:

First Stage

The first stage is directly attached to the tank. The first stage is a valve mechanism which receives high-pressure air of the tank that delivers the air at intermediate pressure to a low-pressure hose that is attached to the regulator’s second stage.

The first stage uses one of two types of valves – the piston valve or the diaphragm valve. The piston valve is simple, comprising only two parts: a large piston and a spring. This valve measures surrounding pressure by allowing water to enter the mechanism and press against one side of the piston. The other end of the piston is seated against the high-pressure air in the scuba tank.

As the diver inhales and reduces the intermediate pressure, the piston moves to allow more air into the system to maintain constant intermediate pressure. Piston regulators are simple but dependable. However, their inner workings tend to be exposed to the harsh environment of seawater or sediment-rich water.

To minimize this, silicone grease may be placed in a cap over the valve to keep water out while transferring the surrounding pressure to the valve. Piston regulators are generally not recommended if you plan to dive from shore.

Diaphragm valve first stages are more complex. They also measure the ambient water pressure, but they prevent water from entering through the use of the diaphragm. These valves can have up to ten moving parts. As the diver inhales and intermediate pressure is reduced, the diaphragm is bowed and pushes a poppet, which allows more air into the system to maintain constant intermediate pressure.

The diaphragm valve prevents the entry of water and it is not adversely affected by sand and dirt. The diaphragm first stage is therefore a better choice if most of your diving is from shore. Diaphragm regulators also tend to be more expensive than piston ones.

Balanced Versus Unbalanced Valves

The valve used in the first stage is either the balanced or unbalanced valve. The balanced valve is one that performs the same regardless of the air pressure in the tank. This is achieved by routing high-pressure tank air around both valve ends to negate the influence of air pressure in the tank.

Regulator first stages that seat directly against tank pressure are called unbalanced regulators. The unbalanced diaphragm was one of the first regulator designs and was in use for years. This valve has a limitation – a malfunction could cause the valve to be forced closed by the tank air pressure, which would suddenly stop all airflow. As a result, all modern diaphragm regulators are now balanced.

Be sure to read the next blog post for more tips on how to choose the best scuba regulator.

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How To Clear Your Dive Mask And Mouthpiece

How To Wear A Dive Mask

Don’t strap a dive mask so tightly to your head that the frame distorts. This will make the mask sit uncomfortably on your face, and it will very likely let water inside. You should adjust your mask so that the water pressure is just enough to maintain a watertight seal. The function of the strap is just to keep the mask in place on your head.

How To Clear Your Dive Mask Underwater

You’ll need to learn to clear your dive mask underwater as your dive mask may become dislodged and floods with water. Occasionally, when your dive mask is fogged, you’ll need to let some water in to wash away the fog and drain the water from your mask.

Your diving mask includes a pocket that encloses your nose. This pocket allows you to equalize your ears by pinching on the nose and breathing against it. This air pocket also allows you to eject water from a flooded mask.

To clear the water from your dive mask, hold the mask firmly against your head so that the skirt makes a good seal. Tilt your head back so that the water is all at the bottom of the mask and exhale gently through your nose. The air you breathe out pushes the water out through the bottom of the skirt where there is a gap between the skirt and your face. Keep breathing out till all the water is drained from your mask.

If you run out of air, just take a second breath from a regulator and breathe out through your nose again to keep clearing your mask. Watch the video below to review how to clear your dive mask underwater.
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You’ll need to master mask clearing, and eventually taking your dive mask off underwater and replacing it again. This is required to pass your open water scuba dive certification! Watch the video below to review how to take your dive mask off, putting it back on and clearing your mask.
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How To Clear Your Mouthpiece

Breathing compressed air tends to dry the mouth and throat. There are times you may want to take out your mouthpiece and let some water into your mouth to moisten it. When you do this, the interior of the regulator will flood with water.

When you put the mouthpiece back into your mouth, remember to exhale first. The water in the mouthpiece will be pushed with the exhaled air through the exhaust port of the regulator.

If you happen to drop your regulator after you have just exhaled, don’t panic. There is a purge control at the front of your regulator. Just push the purge control and this will release a strong flow of air from the tank. This will push out any water that may still be in the second-stage of your regulator. Watch the video below to review to clear your regulator.
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Important Tip:

Whenever you do not have your regulator in your mouth, make sure that your airway is open by exhaling air gently from your mouth. Do this especially when ascending. Your body would have absorbed some gases underwater.

As you ascend, the gases absorbed in your body will start to expand. Exhaling air gently from your mouth will allow these gases to escape through your mouth, thus preventing any potential serious injury.

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Diving At Blue Corner, Palau, Micronesia

Palau in Micronesia in the South Pacific is probably the ultimate dive destination. Consisting of 307 scattered islands, Palau has it all – wrecks, caves, and some of the busiest coral reefs on Earth.

One of the great draws of Palau is the vast range of diving available. Like other island groups in Micronesia, it has colorful reefs cruised by large predators and impressive oceanic species.

Caves and caverns honeycomb walls and reefs throughout the island chain. Fierce battles between American and Japanese forces during World War II mean that that is plenty of wreck diving to be done.
Perhaps the most famous dive site in Palau is Blue Corner. Jutting into deep water at the western edge of the island chain, this site boasts of swirling schools of barracuda, patrolling sharks, eagle rays and Napoleon wrasse.

The Blue Corner is a flat area of reef, which starts at 15 m and runs for about 200 m to a pointy corner that falls abruptly into the ocean depths. A strong tidal current runs through, providing food for the little fishes and other creatures at the bottom of the food chain. These same little fishes and creatures in turn attract middle and upper-chain critters.

You’ll see shoals of schooling black snapper and at least a dozen reef sharks, as well as gorgonian sea fans and feathery black coral trees in the deeper reaches. At the corner, at 16 m , divers can reef hook and hang out to watch as grey reef sharks and schools of fish cruise up and down the reef lip.

The deeper reaches of the Blue Corner harbour large schools of horse-eye jacks. You’ll even catch glimpses of larger pelagics like hammerheads and tiger sharks, marlin, sailfish and schooling yellowfin tuna.

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How To Select A Dive Mask

Dive masks range between $40 to $150. They provide a reasonable view and a means by which the nose can be pinched to clear the ears via the Valsalva maneuver. Most of us don’t require fancy lens configurations, prisms and other gadgetry.

The main concern is selecting a dive mask that fits us well, feel comfortable and have a minimum leakage. The mask should stay securely in place.

A dive mask has a faceplate of tempered glass in one or more sections held by a strong frame. A supple silicone skirt forms a seal between the glass and the diver’s face. An adjustable strap holds the mask in place.

Most masks sold today have the traditional rubber-band type mask strap. These straps tend to pull your hair. The kind of strap that most active divers use is a wide neoprene strap. There is one type of dive mask where the neoprene strap fits over the traditional strap. You will need to remove one side of the traditional strap.

There is another type of dive mask where the neoprene strap replaces the traditional mask strap altogether. The neoprene strap will typically have Velcro strips on each end which loop through the strap holders on the mask and connect back to more Velcro on the strap.

This makes adjustment easy even when the mask is in place and the diver is in the water. In the water, divers also lose their peripheral vision. Good masks have the glass positioned close to the eyes to reduce this problem. The smaller volume of air within the masks also makes them easier to clear if they are flooded with water.

Masks with opaque skirts give a brighter view, but look less attractive. If you prefer a more attractive mask, you can choose a mask with a transparent skirt. If you wear prescription lenses, you can arrange to have a mask lens made in your prescription, at an additional cost, for any mask you buy.

You can watch a video below on how to choose and install prescription lenses into a scuba diving mask. There is also a basic overview of vision problems, and solutions for farsighted and nearsighted scuba mask treatments.

If you wear bifocals or reading glass to read, you might want to outfit your mask with an insert for presbyopia. But bear in mind that you may need to make some correction due to the magnification caused by using the mask in the water.

If the water magnification is insufficient, inexpensive inserts are available for all popular reading-glass magnifications. These inserts are made of soft plastic and sick to the inside of the mask lens like a suction cup. You can remove them if you don’t like them, without damaging the lens.

Tinted lenses have gained popularity over the years. Water absorbs the spectrum of sunlight starting with colors on the low end of the spectrum. Red disappears at a depth of only about 20 feet, orange at about 25 feet, and yellow at about 30 feet. Green disappears at about 40 feet. All colors deeper than 40 feet are seen as shades of blue.

Some divers wear lenses that are tinted pink or red to restore as much color as they can. However, a red mask faceplate will only help bring out the color red in shallow water. It will have no effect on color at a depth where the wavelength we see as red do not exist. Do note also that the use of tinted lens also causes light reduction.

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How To Choose A Buoyancy Compensating Device or BCD

The buoyancy compensating device, often referred to as the BC or BCD, is a complicated piece of life-support equipment. The BC is often priced between $250 to $1000.

There are two main types of BC – jacket-style and back-inflation (‘wings”) BCs. Back inflation BCs cost more than the more common jacket-style BCs. The benefit of using back inflation BCs is they offer less drag and increased stability when the wearer is swimming horizontally underwater. With the air cell behind the diver, the cell does not squeeze the diver’s rib cage when inflated. A diver’s chest remains comfortably unencumbered when he or she is using a black-inflation BC.

The back inflation BC comprises the front harness, the back plate to hold the tank, and the air cell behind. In some models, these components can be mixed and matched to create a custom-made BC. However, back inflation BCs have a tendency to float a diver on the surface face-down since the flotation is behind the diver.

Jacket-style BCs are cost effective and they work well. They come in two general types – the traditional full jacket and that is known as the contour jacket. The full-jacket BC offers great stability with lots of lift. The contour jacket is basically a cut-down jacket with a smaller air cell, which leaves more of the chest area unencumbered. The contour-jacket BC offer good stability, comfort, and less bulk with plenty of lift.

Tips On How To Choose A Buoyancy Compensating Device or BCD:

A BC should fit snugly without binding with the harness adjustments near their medium settings. It is best to try on BCs while wearing the thickest exposure suit you plan to wear while diving.

Inflate the BC to see if it squeezes your rib cage too much when fully inflated. Your arms should fit comfortably in the armholes with no binding. If the armholes are too loose, the BC will tend to rise when you are floating on the surface, especially if the BC is not weight integrated. If the weights are on your body and sinking while the BC is inflated and floating, the combination will tend to make you sink beneath the BC.

Major manufacturers now offer a nice selection of BCs specifically designed to accommodate the female form. Some women also find the back-inflation BCs to be very comfortable.

The BC you buy should fit like a comfortable garment. The BC should not roll around when the cylinder is attached. Controls and pockets should be convenient to find and use. You should also find it easy to take on and off the BC. If you can, make a pool dive in the BC before you buy it. Test it for stability when swimming, for smooth inflation and deflation, for convenient and efficient air dumping in the various swimming positions, and for the way it floats you on the surface.

Do not fully believe sales pitches that claim to float a diver faceup in a survivable position even if the diver is unconscious. Most BCs will not float an unconscious diver faceup on a consistent basis, and there is no assurance that his or her nose and mouth will be out of the water.

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Scuba Diving And Snorkeling At Pulau Payar Marine Park, Malaysia

My children are still young, so I’m currently encouraging them to snorkel to begin appreciating the fascinating underwater world.

We went to the protected Pulau Payar Marine Park, in the northern part of Straits of Malacca. We got to Langkawi Coral in a glass bottom boat. We alighted at the large floating platform at Langkawi Coral moored off Pulau Payar.

The protected area means that even just 10 metres from shore, there is plenty to see while snorkeling. My children and I put on our life jackets, masks and snorkels. We held hands and we just put our faces into the water.

The kids were excited to see Nemo, their favorite clownfish swimming among the sea anemone, baby sharks measuring about thirty inches in length, and huge rabbit fishes, a delicacy among the Chinese during Chinese New Year.

I hope in years to come, this snorkeling experience will inspire my kids to take up diving. I came across this excellent footage on YouTube, capturing exactly what we saw. Hope you’ll enjoy the footage! How I longed to join the folks scuba diving right beneath us!

Where is Pulau Payar Marine Park Situated:

The Pulau Payar Marine Park is about thirty kilometers south of Pulau Langkawi. It covers two nautical miles off four islands – Pulau Payar (the largest), Pulau Kaca, Pulau Lembu and Pulau Segantang. All four islands are uninhabited. Both hobby and commercial fishing are strictly prohibited. There is no accommodation on the islands.

How To Get To Pulau Payar Marine Park:

A day trip to Pulau Payar Marine Park is the only option for most tourists, who can go to Pulau Payar Marine Park from Kuah on Langkawi Island, Kuala Kedah on the Malaysian mainland and Penang Island. If you plan to leave from Kuah like we did, you can book your trip at the office of the Langkawi Coral at the Kuah Ferry Terminal, which cost around RM220 per day.

For this price, the company will pick guests up from their respective hotels, provide lunch and the use of their reef-viewing platform. All their snorkeling equipment is also at the guests’ disposal. From Kuah, the boat ride to Pulau Payar Marine Park will take about 45 minutes. Island and Sun at Kelanas in Kuah provides a similar service, for RM150. This price does not include hotel transfers and they take visitors out to Pulau Payar in small speedboats. If you plan to go to Pulau Payar Marine Park from Penang, the journey will take a little more than an hour.

To book a tour you can visit


Camping is allowed with permission from the Fisheries Department at Alor Setar, the capital of Kedah state. They can be contacted by telephone at 04-732 5573.

What You Can Do At Pulau Payar Marine Park:

Pulau Payar offers four sandy beaches, which combine to provide a total length of about 200 meters. The surrounding waters offer an average visibility of between 9 to 15 meters. You can scuba dive, snorkel, swim and picnic there. Many visitors do the “Introductory Dive” at this marine park. Picnic tables, barbecue pits, gazebos and restrooms are available. There are two tracking trails for visitors to explore the flora and fauna on the island.

What You Can Do At Langkawi Coral:

There is a floating platform measuring 49 meters X 15 meters moored off Pulau Payar where you can dive and snorkel. There is a platform for introductory course in scuba-diving, a wading deck for swimming and beginners’ snorkeling. There is a sun deck for sunbathing. Shower facilities are available. There is also a snack bar onboard.  My husband was too lazy to get wet that day, so he chose to view the underwater scene from the Underwater Observation Chamber located at the bottom of the platform more than ten feet below the sea.

More Good Places To Dive At Pulau Payar Marine Park:

Coral Garden offers spectacular views of multicolored and vibrant soft corals. It is located at the southwestern tip of Pulau Payar. Other popular spots are the flat terrain to the east of the island, and the area to its west around Pulau Segantang that offers steep diving condition.


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Top 10 Underwater Photography And Video Filming Tips

With the vast array of colorful marine life, underwater photography and video are now the most popular underwater scuba diving activities worldwide.

To make each scuba diving trip worthwhile for you, below are top ten underwater photography and video filming tips to help you capture better underwater photos and images:

  1. Get as close to your subject as possible. Use lenses with the widest possible angle of view to frame your subject. This is to minimize the diminishing of colors underwater and to ensure that the contrast of images is not compromised.
  2. Use a strobe for still cameras or video lights for video, to bring out the color of your subjects. If you are not using video lights, you can obtain good color in video by using a red or orange filter over the video camera lens in shallow water of about 30 feet deep.
  3. Aim your artificial light to illuminate your subject, and not at the water between the lens and the subject. This is because even the clearest water has particles suspended in it. Light shining on these particles will create the appearance of “snow” in your images, or backscatter. Move the artificial light source away from the camera lens to minimize the backscatter. Use artificial light only if you are within 5 feet of your subject to effectively light your subject without the creation of backscatter.
  4. Balance the intensity of the artificial light with natural light so that the resulting image is seamlessly lit.
  5. Separate your subject from the surrounding background clutter which will only divert  attention from your subject. You can easily do this by shooting upward toward the surface instead of horizontally toward the reef or downward toward the bottom.
  6. Maintain your camera carefully. Salt water in the long term will have a detrimental effect on your camera, optics and electronics. You should purchase flood insurance if you are using expensive photography or video equipment as it is less hardy than your regular dive equipment.
  7. Take time to become familiar with a dive site by diving the same site over a period of several days. This way, you’ll learn where the marine residents live, and you’ll be better prepared to capture them on film, tape or digitally.
  8. While filming, spend some quality time with your subject. Once you find a subject that interests you, cover all angles before moving on.
  9. Underwater photography and video involves the handling of equipment in addition to your scuba diving equipment. You should be fairly confident of your buoyancy and scuba diving skills before handling any photography and video equipment.
  10. Remember to breathe normally and you should never hold your breath when scuba diving. This is because most of us have a tendency to hold our breath when looking through the viewfinder.


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