Frequently Answered Questions - FAQ

Products - Apeks Regulators

It is difficult to give you a meaningful answer regarding breathing performance of ANY of the primary regulators we sell, including our own DGX Gears brand, in relation to other specific brands or models we don't sell. However, perhaps we can put the performance issue in perspective: In reality, any modern balanced general purpose scuba regulator, designed to perform to EN 250 standards and properly maintained, is capable of delivering gas more than adequate for the needs of two sport divers (primary plus an octo). That's not to say there aren't poorly performing sport regulators in the market, but you can't buy them at Dive Gear Express.

There is no perfect regulator; they all have strengths and weaknesses that make each uniquely more or less suited to your needs. Keep in mind that a big brand name and high price are factors that rarely equate to better performance or better value. When choosing regulators at Dive Gear Express, make your decisions based on considerations that are less about "performance" and more about matching the regulator to the diving application. For example, an extreme exposure (i.e. deep and cold) technical diving regulator is a poor choice for shallow tropical sport diving. Beyond the features of the regulator itself, you should consider the supplier along with how the model was designed and has been supported. As an independent servicing dealer, we stock complete regulator packages, components and parts with online ordering and same day shipping.

With one exception, all the diaphragm regulators we sell are environmentally sealed, including the DGX Gears D6, Dive Rite XT1, Mares 28XR, and Apeks XTX series (DS4, TEK3, DST, FSR) first stages. The Poseidon Xstream is a unique balanced rolling diaphragm ball valve design that is not environmentally sealed because it relies upon a built in thermo-dynamic anti-freeze system to remain ice free.

Piston regulators are not typically described as environmentally sealed in the conventional sense because the internals are protected by other methods inherent in their design. The DGX Gears XTRA & FIRST, Dive Rite RG5400, and Mares R2XR are piston first stages.

The need for sealing a first stage is not relevant to most types of diving, for more information read our TekTip titled Environmentally Sealing SCUBA Regulators.

The current XTX series first stages differ in the orientation of their ports and cosmetics. Although their price varies, they are all over-balanced diaphragm design with an environmental seal and they all use the same periodic service parts kit. All the Apeks regulator packages are EN250 certified to a depth of {660 fsw | 200 msw} and have identical extreme performance breathing characteristics that make Apeks XTX regulators a popular choice of experienced sport and technical divers worldwide.

For a deeper explanation of all the model variations read our TekTip Apeks XTX Series First Stage Differences.

The current Apeks XTX series second stages are all identical except for cosmetics and one minor feature. Although their price varies, the XTX series second stages are a pneumatically-balanced downstream design with a large ergonomic venturi control lever, can be reconfigured to reverse the side of the hose inlet (left or right), and they all use the same periodic service parts kit. All the Apeks regulator packages are EN250 certified to a depth of {660 fsw | 200 msw} and have identical extreme performance breathing characteristics that make Apeks XTX regulators a popular choice of experienced sport and technical divers worldwide.

For a deeper explanation of all the model variations read our TekTip Apeks XTX Series Second Stage Differences.

Popular for stage/deco/sidemount technical diving applications, the ambidextrous and reversible second stage regulator designs ultimately offer the same feature: the orientation of the hose inlet and thus the hose routing can be either the typical right-hand side or the uncommon left-hand side of the diver. The difference is how this reorientation is accomplished.

In the few second stage designs that are reversable, the regulator body is opened, the inside components are removed, reoriented to the opposite side and the regulator is reassembled. Both the Dive Rite XT series and Apeks XTX series second stages are reversable. The Dive Rite XT series second stages require a mirror image part for the venturi be exchanged to accomplish the reversal. The Apeks XTX series second stages do not require any additional parts for the reversal. Both Dive Rite and Apeks describe the process of reconfiguring the regulator as both quick and simple, however they also both recommend this be done by a regulator technician. It takes our experienced reg tech about 15 minutes to do the reverse and bench test, if you don't interrupt them with any questions.

Ambidextrous second stage designs are inherently right or left when you simply put the regulator in your mouth. The design of the regulator is symmetric about its longitudinal axis; the body and mouthpiece has no "top and bottom" or "up and down". The exhaust on an ambidextrous design will always be on the end the body directly opposite the hose inlet and bubbles come out the end not the bottom. Ambidextrous regulators are typically referred to as side-breathers and we offer the SXS downstream second from Mares plus the Xstream upstream second from the OG of side-breathing regulators - Poseidon.

The Apeks XTX second stages (XTX40, XTX50, XTX200) are a reversible design that can be converted from a standard right-hand hose inlet configuration to an uncommon left-hand configuration. However, the Apeks distribution center in the US does not stock the XTX series reversable second stages from the factory in the left-hand configuration. Apeks describes the process of converting the regulator to a left-handed hose inlet as both quick and simple, however they recommend this be done by a technician trained to service Apeks products.

Because we do the reconfiguration in our facility using our Apeks technician, there is a small increase to the price of the Apeks XTX series standard second stage to cover the cost of converting and testing the now left-hand second stage prior to shipping. If you want to learn about what is involved, you can read the Apeks technician instructions at Converting the XTX Regulator to Left Handed Configuration.

The manufacturers of all the general purpose SCUBA regulators we stock describe them as suitable for use in warm, temperate and cold water conditions. Based on testing standards we define those water temperature ranges as follows:

  • • Warm water is greater than {68°F | 20°C} to a maximum of {90°F | 32°C}.
  • • Temperate water is between {68° to 50° F | 20° to 10° C}.
  • • Cold water is less than {50°F | 10°C} to a minimum of {40°F | 4°C}.
  • • Freezing water conditions below {40°F | 4°C} incurs significant additional risk that requires specialized training and specialized equipment.

Among the regulators we stock, only the Xstream series is described by Poseidon as suitable for diving under ice in freezing seawater conditions down to {29°F | -2°C}. However, the XTX series is a close second, described by Apeks as suitable for use down to {36°F | 2°C} and a popular choice among "ice divers".

First stage regulator ports:
7/16" port = HP
3/8" port = LP (or IP)
1/2" port = MP

First stage regulator pressure:
high-pressure = HP
low-pressure = LP, IP, or MP

"Low" is sometimes called "Intermediate" or "Middle" pressure and all three terms are referring to the exact same regulated output pressure of the first stage.

Scuba hose connectors
second stage 9/16" = LP
inflation Shrader = BC

Mated fittings that can be quickly disconnected without tools = QD

In the 90's some regulator manufacturers (notably Apeks, Aqualung, and Mares) started offering some versions of their first stages with an oversized 1/2" low-pressure port. The oversized port has an optimized gas flow path and should be used to supply the primary second stage. (Mares calls it a DFC port.) While the oversized and optimized port does slightly improve machine test results in simulations, most divers found it does nothing significant for actual in-water breathing performance and also inconveniently requires a non-standard regulator hose.

Today, most manufacturers have deprecated their oversized port on first stages for the recreational market, although it continues to be available on versions for the military market. If you are seeking a 1/2" regulator hose, instead your best strategy might be to just plug the oversized port and use one of the other standard size low-pressure ports. If you insist on a regulator hose with a native 1/2"-20 UNF fitting, then take a look at these non-standard regulator hoses.

The typical intermediate pressure setting for most first stages is around {135 psi | 9.5 bar}. Upon request a Dive Gear Express service technician will adjust the IP to your specified non-standard setting prior to shipment but only for diaphragm first stage designs. We also offer 3rd party modifications to the Apeks DS4 to change the behavior of the intermediate pressure; enabling use with constant mass flow orifices and needle valves found on some types of rebreathers.

The IP adjustment on diaphragm type first stages is simple enough for most divers to learn to do themselves. The IP adjustment screw is located under the environmental seal cap on the bottom of the regulator. The only tools needed are a round surface spanner wrench to remove the cap, a hex key set to turn the adjustment screw to change the IP setting, and an IP pressure gauge to measure the setting. These are all available in our Regulator Service Tools category. A few minutes with a knowledgeable peer or Google will show you how.

YES! Dive Gear Express offers regulator service on all models we currently sell. Dive Gear Express is an authorized service center for Apeks, Dive Rite, Mares XR, and Poseidon regulators. We of course also provide service for our house brand DGX Gears regulators. For all the details visit SCUBA Regulator Maintenance Service at Dive Gear Express.

For regulator brands that we are not certified to service, we recommend using a factory authorized service center nearest you. Three long established U.S. based companies that specialize in factory authorized regulator service for most brands are Airtech in North Carolina, RegTech in Wisconsin, and Pacific Scuba Repair in California.

The only difference between our unbranded SPG "brass & glass" models and similar branded SPG models is the logo and price; any SPG will work on any regulator regardless of brand and they are all manufactured by Termo Industra of Italy with equal quality construction. Our unbranded generic SPG models have a lower retail price as a result of being sourced directly from the manufacturer. Our long experience with the unbranded and branded "brass & glass" SPG models has been they all have similar reliability and durability in the field. Regardless of brand, every product we sell is backed by Dive Gear Express 5-star quality customer service. For more information see our TekTips titled SPG Depth Ratings and Inside Submersible Pressure Gauges.

The only significant difference is the branding and price; any DIN-to-Yoke adapter will reliably work on any DIN regulator regardless of brand. The designs differ a little but they are all of equal quality chromed brass construction. The generic value priced DGX adapters are available in your choice of black or silver color, and features a nice sized handwheel which makes it easy-grip to install and remove from the valve.