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Monitoring your air is paramount when you go scuba diving. But how do you know how much is left in your tank?
Enter the submersible pressure gauge (SPG). A SPG constantly reads your tank throughout the dive. In this guide, we’ll show you the best scuba pressure gauges on the market and highlight some things to consider when choosing the best SPG for you.
Despite being somewhat bulky (this gauge meassures 13″ x 7″ x 3.5″), the Mares Mission 3 is lightweight at only 0.3 kilos (0.7 pounds). It is a great all-around gauge with an SPG, a depth gauge and an underwater compass.
This popular three-gauge console comes with both imperial and metric readings. For the SPG, it has a readout from 0-360 bar (0-5,000 psi) with a low on air red color zone starting at 50 bar (1,000 psi). Both imperial and metric versions have a luminous face and dial that can be charged with the beam of your underwater torch.
For the depth gauge, it has a readout from 0-70 m (0-230 ft). Both versions have a maximum depth indicator which stops and remains at the greatest depth of your dive. At the top end of the console is an underwater compass that has a rotating bezel, lubber line, and a numerical mark at 30° interval and dotted marks at 10° interval.
All the gauges are encased in an optimally angled shock resistant case. A pro of this console is that the depth gauge can be upgraded and changed to a dive computer via the Mares Puck Pro+ dive computer system.
Functions: SPG, Depth, Compass, Temperature Reading Options: Metric + Imperial
The Scubapro three-gauge SPG comes in at 0.4 kgs (1 lb), and is another all-in-one SPG console to consider as a primary instrument. This console has an SPG with a readout from 0 to 6,000 psi (410 bar) which is one of the highest readout ratings for SPGs. While it has clear numerical markings, you will appreciate the large red color code for low on air which is conservatively set in this SPG at 1,000 psi (70 bar).
At the middle section of the console is the depth gauge. It has a readout from 0-200 ft (60 m) with a red color zone starting at 140 ft (42 m) which indicates that you have reached the maximum depth limits set for recreational scuba diving. The depth gauge also has an internal thermometer that can read from 0 to 120°F (0-28°C) with a 20°F interval mark.
Found at the tip of the console is the oil-filled underwater compass. It has all the basic features for navigational ease like a lubber line, rotating bezel, and numeral markings at 30° interval. All the instruments in this console are encased in a durable impact-resistant boot that has multiple lanyard attachment points.
Functions: SPG, Depth, Compass, Temperature Reading Options: Metric + Imperial
Considered as one of the best all-in-one SPG, the Tusa Platina looks like a 2-gauge console but actually has 3 gauges. The front face of the console is made up of a SPG and depth gauge. The SPG has a readout from 0 to 400 bar (0-6,000 psi) with an internal thermometer that reads from 0 to 40°C (32-40°F). The SPG markings are color coded with blue from 100 to 400 bar and red from 0 to 50 bar. Likewise, the depth gauge has a readout from 0 to 60 meters where a blue-coded zone is presented from 0 to 20 meters (the maximum depth for open water divers) and a red-coded zone from 30 to 60 meters which indicates that you are too deep.
When you flip the console, you will see an underwater compass. It has a lubber line, rotating bezel and the markings are in a 30° increment with 10° dotted interval marks. The 3 gauges are encased in an impact-resistant rubber that is rated to be one of the toughest SPG cases in the market.
If you are looking for a lightweight SPG console that is both rigid, efficient and ideal for frequent travelling, then you may look at the Scubapro 2-gauge console. Weighing only 0.8 kilograms (1.7 pounds), this 2-gauge console is composed of an SPG and a depth gauge that is encased in an impact-resistant boot.
The SPG uses the imperial system that has a readout from 0 to 5,000 psi. The markings in the SPG are clearly indicated and marked out with 500 and 1,000 psi increments. It has a luminous dial and face that grows brightly in the dark and can easily be charged with an underwater torch. For the depth gauge, it is oil filled and has a readout from 0 to 150 feet. Aside from the bright orange indicator mark at 10 and 20 feet which gives you an indicator for decompression and safety stops, it also has a maximum depth indicator (MDI) that will record the greatest depth of your dive.
Weighing only 0.5 kilograms (1.2 pounds), the Oceanic Max-Depth SWIV Combo Gauge is another popular lightweight SPG that is designed for frequent use and travelling. This is an imperial type 2-gauge console that is composed of an SPG and a depth gauge.
The SPG has a readout from 0 to 5,000 psi and an internal thermometer which can read from 0 to 100OF. The SPG markings are highly visible with a red color code from 0 to 500 psi indicating low on air. Similarly, the pressure gauge has a readout from 0 to 200 feet with a red color code just after the 120 feet mark all the way to the 200 feet mark which indicates that you are outside the depth limits of recreational scuba diving. Both the SPG and the depth gauge are encased in an impact-resistant boot that has multiple eyelets for clip or lanyard attachment.
If you are fond of equipment rental, then most probably you have used the Aqua Lung 2-gauge console. This popular and best-selling instrument has 2 gauges: the SPG and the depth gauge.
The SPG used in this instrument uses the metric system and has a readout from 0 to 350 bar. Aside from having a large face, the markings in the SPG are clear and large with a marking interval of 1,000 psi and a red color zone for low on air starting at 50 bar. The SPG also has an internal thermometer that can measure anywhere from 0 to 40°C.
At the tip of the console is the depth gauge. It has a readout from 0 to 60 meters with a needle that indicates your maximum depth. With regards to the markings of the depth gauge, you have to be aware that it is not equally divided. The markings are progressive which initially starts at a 3-meter interval and increases to a 10-meter interval.
One more thing, try to flip over this dive console and you will find a white circular plastic sheet that also acts as a writing slate.
Being the 2-gauge counterpart of the Mares Mission 3, the Mares Mission 2 still has the same simple yet highly functional dive console. Except for the underwater compass found in its 3-gauge counterpart, the mares Mission 2 has an SPG and a depth gauge.
The instruments used in this 2-gauge dive console use the imperial system. The SPG has a read out from 0 to 5,000 psi with clear marking intervals and a red color zone for low on air starting at 1,000 psi.
The depth gauge in this dive console has a read out from 0 to 230 feet with a highly visible red needle which acts as a maximum depth indicator. And what’s good with this depth gauge is that it can be upgraded to a dive computer using the Mares Puck dive computer system.
Functions: SPG, Compass, Temperature Reading Options: Metric + Imperial
Looking for a standalone SPG design that actually has 2 gauges? Then take a look at the XS Scuba Pressure Gauge/Compass Combo. The front part is an imperial-type SPG that has a readout from 0 to 5,000 psi and has an internal thermometer that can measure from 0 to 100OF. While the markings are only in black, you will appreciate the red color zone from 0 to 500 psi which indicates that you are already low on air.
Flip the SPG and you will be surprised to find an underwater compass. It is liquid-filled with a ratchet rotating bezel. Its numerical headings have 30° increments and 10° line indicator marks. Both face and dial of the SPG and compass are luminous and can easily recharge with a direct beam from your underwater torch. Likewise, both SPG and compass are encased in a rubber boot that has a hole at the end for swivel attachment.
If you are into technical diving and looking for a non-booted and exposed standalone SPG, then you may look at the XS SCUBA Highland Brass and Snap SPG. This Italian made SPG uses the imperial system with a readout from 0 to 5,000 with clear numerical marks at 1,000 psi intervals. It also has bolded linear marks at 500 psi interval and plain linear marks at 100 psi interval. (Bar readings also available).
This SPG is encased in a nickel-plated brass housing that has a bolt snap with an integrated 360° stainless steel swivel. The only downside on this SPG, which you should be aware of before diving, is that the markings are NOT color coded and do not expect a red color code for a 500 psi low on air reading.
Functions: SPG, Temperature Reading Options: Metric + Imperial
Standalone and booted: those are some of the descriptions of the Oceanic SWIV Pressure Gauge. Recommended for technical diving, this standalone SPG has a readout from 0 to 5,000 psi.
While it has a small size, the markings are highly visible and is complimented by the white luminous face with black numerical marks at 1,000 psi interval and linear marks at 200 psi interval. The 500 psi low on air zone is also highlighted with a red color code. This SPG also has an internal thermometer at the bottom that can measure anywhere from 0 to 100°F.
A fully-filled scuba tank that has 3,000 psi (207 bar) of compressed air. Divers should ascend towards the surface once they reach low air, which is around 500-700 psi (34-50 bar).
Determining air pressure in your tank requires the use of a submersible pressure gauge (SPG). SPGs are a precision instrument that reads the exact pressure of your tank. While diving, you should monitor your SPG every few minutes. This way, you will know how much air is left in your tank and avoid a catastrophic out-of-air situation while underwater.
As a rule, never dive without an SPG or with a broken SPG.
Buying a Submersible Pressure Gauge: Things to Consider
Shopping for SPG may sometimes give you a headache for one reason: there are a lot of choices. Some scuba gauges solely have SPG capabilities, while others come with all the bells and whistles of a compass, depth gauge, thermometer, and more.
The SPG that you should choose should have at least these basic features. First, the marks should be color coded. Usually, green indicates full, yellow for midway and red for low on air.
Second, the needle or dial should be fluorescent. This makes it easy to see in low-light conditions.
And lastly, the internal face should be luminescent. The second and third features mean that your SPG will glow in the dark and this is very important if you’re exploring gloomy areas or during a night dive. This also means that both the dial and the face can be easily charged by pointing the beam of your underwater torch at the gauge.
Standalone or Console
The most common set-up of SPG is the console type. Generally, a console has 2 displays: a depth gauge and an SPG which is attached to a high pressure hose. Similar configurations would involve a 3-display console where an underwater compass is usually attached at the top-most end.
SPGs are packaged in 2 forms: stripped down or booted. Console SPGs are the booted type where they are covered with either plastic or rubber. Stripped down SPGs are usually standalone instruments used in technical diving. While it creates less drag than the booted SPGs, stripped down SPGs are exposed and may need extra care against hard objects like rocks or during transport.
Metric or Imperial
If you are used to the metric system (in this case “bars”), don’t be surprised to see SPGs using the imperial system (in this case PSI or pounds per square inch). Typically, SPGs manufactured in the US use the imperial system while European made SPGs use the metric system. You should choose the system you are most familiar with or the system that matches the area you’ll be diving in most often.
Although we had already mentioned, you should know that a fully filled tank should have 3,000 psi or 207 bar and low on air is set at 500 psi or 34 bar, although this is conservatively raised to 50 bar or 725 psi.
Before we end this article, divers have a tendency to configure their equipment so that they can achieve comfort, fit, trim and balance while underwater. While this can easily be done in other scuba equipment, please do not configure your SPG (except only for lanyard and swivel attachment). SPG are precision instruments and handle high pressure air. If you think you need adjustments or check for calibration, do not attempt to do it yourself. Always have it serviced to an accredited dive shop or service center.
FAQ – Frequently Asked Questions about Scuba Pressure Gauges (SPG)
What does a Scuba SPG stand for?
SPG in scuba diving stands for submersible pressure gauge.
What is gauge pressure in scuba diving?
Gauge pressure in scuba diving is the amount of air or breathable gas left in your scuba diving tank. A pressure gauge measures this gas/air in bar or psi.
Do I need to use a SPG in scuba diving?
Yes, using a SPG is essential in scuba diving to reveal how much air or gas is left in your scuba tank. How fast you consume air differs from dive to dive and from day to day, there is no way to obtain an accurate reading without this pressure gauge. Sometimes, the air pressure gauge can be linked to an air-integrated diving computer.