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Dive Class Questions

How old do I have to be to be certified?

The minimum age for certification is 10 years old.

What equipment do I need to supply to learn to dive?

You need to have personal gear. That includes a mask, snorkel, boots, fins, and a weight belt.  We will supply the rest of the gear for your training. When you purchase all 5 items for your Open Water course with us, we provide a $100 allowance towards your equipment purchase. 

What equipment do I need for check-out dives?

You will need to purchase gloves. A wet suit and a hood may be purchased or rented.

Rental Equipment FAQ

What equipment do you rent?

We will rent tanks, BCD’S, reg. sets, pony bottles, wet suits, and hoods. We do NOT rent gloves, weight belts, or lead.

Can anybody rent scuba gear?

No. You must be a certified diver and provide proof of certification. A credit card must be supplied in order to rent gear.

Diver Certification FAQ

Do I need a diving certification in order to receive a sport diving air fill?

No. To receive an air fill, one does NOT require a scuba diving certification. WHY? Many persons involved in paint ball shooting own scuba cylinders in order to transfill their own smaller cylinder. Furthermore, often, the person who drops off or picks up a scuba cylinder is not a diver (for example, a husband who is not a diver drops off and picks up a cylinder for his wife who is a certified diver etc.) To receive a fill with any nitrox mixture of 40% or less oxygen content, we DO REQUIRE a nitrox diver certification.

What type of certification must I have to receive a technical diving gas fill?

To receive a fill with any hyperoxic mixture greater than 40% oxygen content (including pure oxygen), we require a technical diver or equivalent certification. To receive a fill with helium mixtures, a trimix diver or equivalent certification is required. We will observe any specific mixture restrictions that appear on your c-card. We interpret normoxic trimix to mean a helium mixture with an oxygen content between 18% and 24%.

What if someone else is receiving fills on my behalf, and they don't have the appropriate certification?

Unless you have made prior arrangements, we will not allow anyone who lacks appropriate certification to receive a cylinder with breathing gases other than air, because divers should always analyze and label their own cylinder contents. Those divers should be the ones picking up the cylinders – period.

Filling Procedures FAQ

How fast do you fill cylinders?

Our target fill rate is 500 psi per minute. This means that the standard aluminum 80-cubic-foot cylinder with 500 psi residual takes approximately five minutes to fill. In addition to extending cylinder life, at this fill rate, there is not enough heat created to significantly affect the final pressure.

What is the procedure for leaving a cylinder to be filled?

When you drop off a cylinder to be filled, you must complete a work order tag to indicate the desired final contents and pressure, along with your name and contact information. The work order tag is attached to the cylinder and, upon request, you receive a numbered claim check.

What if I don't have my claim check when picking up a cylinder?

If a claim check was issued, we will not release the cylinder(s) until the claim check is produced. If you can’t find the claim check, we will accept your photo identification as long as it matches the name on the work order tag. Please make prior arrangements if someone else will be picking up the cylinder and they won’t have the claim check.

Why don't you put cylinders in water baths when you fill them?

The counterproductive practice of wet filling in the scuba industry is declining, but still common even in the face of strong arguments against the practice.

Will you fill a cylinder in a water bath upon request?

Upon request, we’ll gladly:

> Completely fill your cylinder in a dry environment
> Immerse the cylinder in a clean fresh water bath for 5 minutes to rinse and check for leaks
> Dry the valve
> Check the pressure

Do you partial pressure blend cylinders?

Yes. We have the capability of partial pressure blending cylinders. We can generate our trimix via partial pressure methodology and/or by using a process known as continuous atmospheric entrainment. This allows us to deliver the final mix directly into your cylinder without any need to partial pressure blend.

Oxygen Service FAQ

What do "nitrox ready" and "suitable for oxygen service" mean?

In the diving community, oxygen (O2) service means the materials are both:

> O2 Compatible — compatible with high concentrations of oxygen
> O2 Clean — free of hydrocarbon contamination

When the diving community prepares an item for oxygen service, they generally think in terms of washing it with a detergent, replacing rubber parts such as O-rings and seals with oxygen-compatible equivalents, and reassembling with oxygen-compatible lubricants. However, oxygen cleaning as performed in the high-tech industry has a very different standard. True oxygen cleaning actually takes place in a special clean room, whose atmosphere is free of dust and contaminants. Once the component is free of hydrocarbons and other combustible elements, it is sealed within a sterile environment and never again exposed to normal atmospheric dust, moisture, and contaminants. This is what “high-tech industry” means when they describe something as oxygen clean.

Some manufacturers offer diving products labeled “nitrox ready”, meaning those components are free of hydrocarbons and other flammable contaminants. The lubricants used in assembly are noncombustible. The O-rings and seals are made from Viton or other oxygen-compatible materials. These components are not, however, assembled in a clean room or sealed in a sterile environment. As a result, the manufacturers do not label their equipment as “suitable for oxygen service”, although they meet the most commonly used oxygen service criteria in the diving community.

How do I prepare my cylinder and valve for oxygen service?

Many valves are delivered from the factory containing O-rings and lubricants that are not oxygen-compatible. Most cylinders that have been in use have some level of hydrocarbon contamination. To make a cylinder and valve suitable for oxygen service, they must be disassembled and cleaned of hydrocarbon contamination, and reassembled with oxygen-compatible O-rings and lubricant. This process requires training, special materials, and is time-consuming. For a very reasonable fee, Benthic Scuba can prepare your cylinder and valve for oxygen service.

How do I know that my cylinder and valve are suitable for oxygen service?

Once a cylinder and valve have been prepared for oxygen service, a special sticker (or, often, a special version of the evidence of visual inspection sticker) is affixed to the cylinder. Unless the sticker explicitly states that a cylinder and valve are suitable for oxygen service, they are not. If the cylinder is ever filled with anything other than oxygen-compatible breathing gases, it is no longer suitable for oxygen service, and the sticker should be removed. Even with the best quality fills, hydrocarbon contamination can build up over time. Benthic Scuba recommends that the cylinder and valve should be prepared for oxygen service each time the cylinder is hydrostatically tested.

When does my cylinder or valve need to be suitable for oxygen service?

Your cylinder and valve must be suitable for oxygen service any time they will be exposed to a gas mixture containing more than 40% oxygen. While sport diving nitrox and technical diving trimix don’t require the cylinder and valve be suitable for oxygen service, many fill stations blend directly in the tank by first adding 100% oxygen, then topping off with air. This process, known as partial pressure blending, requires the cylinder and valve to be suitable for oxygen service. In practice, almost all nitrox and trimix cylinders are suitable for oxygen service because partial pressure filling is so common.

Does Benthic Scuba require my nitrox cylinder to be suitable for oxygen service?

Mostly. Any nitrox mixture, premix or custom blend, at Benthic Scuba less than or equal to 40%, does NOT require (although we recommend) your cylinder and valve to be suitable for oxygen service because our nitrox for < 40% can be pre-blended up to approx. 3000psi. Any nitrox exceeding 40%, would require your cylinder and valve to be suitable for oxygen service.

Does Benthic Scuba require my trimix cylinder to be suitable for oxygen service?

Mostly. Because we can pre-blend our trimix via a continuous atmospheric entrainment blending system, hyperoxic gases never come in contact with your cylinder. Thus, at Benthic Scuba, our trimix fills do NOT require that your cylinder and valve are suitable for oxygen service (although it is recommended).

NOTE: The U.S DOT has interpreted its regulations stating that DOT-3AL (aluminum) scuba cylinders cannot be charged with oxygen enriched air to a service pressure greater than 3000psi. Thus, aluminum cylinders with pressure ratings greater than 3000psi (eg. Catalina 100s are filled to 3300psi as well as compact scuba cylinders) cannot be charged with oxygen enriched air as mandated by the DOT.

Cylinder Qualification FAQ

When exactly does my visual inspection or hydrostatic test expire?

A visual inspection expires one year following the inspection. A hydrostatic test expires five years following the test. Because neither a visual inspection sticker nor hydro retest mark show the day of the month performed, the practice in the scuba industry is that the valid period expires on the first day of the month shown. If you have an official written record, including the serial number of the cylinder and the exact date of the inspection or hydro, the expiration date is at the beginning of the day indicated on the written record.

What is an eddy current exam?

This examination uses a tiny current of electricity and is performed on some types of aluminum scuba cylinders to assist in the detection of cracks in the threaded neck area. It alerts the inspector to specific locations on the neck threads that need further evaluation. The devices using eddy current technology are sold under the brand names Visual Plus, Visual Eddy, and Simple Eddy. The exam is notorious for false positives as a result of poor operator technique and is intended only to supplement, not replace, the visual inspection. Luxfer recommends eddy current tests be performed only on their aluminum cylinders made from 6351-T6 alloy. However, many dive shops require an annual eddy current exam on all aluminum cylinders before filling, regardless of the type of alloy. Eddy current exams are not meaningful on any type of steel.

Does Benthic Scuba require an eddy current test on all aluminum cylinders before filling?

Yes. We require an eddy current exam on all cylinders made from aluminum alloy.

Why do aluminum cylinders made from the 6351-T6 alloy require an eddy current test?

This particular alloy has a history of a phenomenon known as sustained load cracking (SLC) that can cause a cylinder to fail. Aluminum scuba cylinders manufactured in 1982 and 1983 require particular attention because the 6351-T6 alloy used during that period had a higher lead content which makes the cylinder more susceptible to SLC. By 1990, the US aluminum cylinder industry was using a different alloy, known as 6061-T6. There are no indications that the 6061-T6 alloy has problems with SLC, and no steel cylinder has ever shown problems with SLC.

Will Benthic Scuba fill my aluminum 6351-T6 alloy scuba cylinder?

Yes, provided the cylinder had an eddy current test within the last 12 months.
Benthic Scuba does not recommend renewing the visual inspection or hydrostatic test for aluminum 6351-T6 alloy scuba cylinders because of problems with sustained load cracking (SLC) in those cylinders. We recommend that aluminum 6351-T6 scuba cylinders be removed from service. DO NOT BE FOOLED into purchasing a 6351-T6 alloy scuba cylinder from eBay, a yard sale, etc. These cylinders are potentially deadly, have proven to be deadly, and are the equivalent of a ticking time bomb. It’s not a matter of “IF” it will fail, but “WHEN”. Most local dive shops will not fill them. Period!!!

What cylinders require an interior inspection before Benthic Scuba will fill them?

Our fill station operators are trained to perform a cursory examination of each cylinder before it is filled. We require an interior inspection whenever we encounter a cylinder with:

> Leaks
> Rattles, sloshes, or other unusual noises
> Abnormal weight
> Zero pressure, i.e., completely empty
> Foul-smelling contents

What cylinders does Benthic Scuba refuse to fill?

Regardless of what appears to be a valid evidence of inspection sticker or hydrostatic test stamp, we consider some cylinders unsafe to fill. We will not fill any cylinder with:

> Heavy corrosion, especially line corrosion at the boot
> Exterior damage, such as a dent, gouge, bulge, or deep pit
> Evidence of exposure to high temperatures, such as scorching
> Vinyl or other unusual or unrecognized coatings or paints
> Valve using a lead plug overpressure burst disk
> Attributes that would cause it to be permanently removed from service
> It is illegal in Canada to fill, visually requalify, or re-hydrotest any cylinder that lacks a TC/CTC stamp that was manufactured after 01/1993.

What cylinders should be permanently removed from service?

According to the US Department of Transportation regulations, the Compressed Gas Association guidelines, or manufacturer recommendations, some cylinders should be permanently removed from service. Our fill station operators will not fill the following cylinders:

> Any with missing or illegible TC/DOT required markings
> Any with a Condemned marking
> Any aluminum with a + mark
> Any aluminum with a round or beveled bottom
> SP6688 Morris (Military Division)
> SP6575/6576 Kaiser Industry
> SP6020 Kaiser Industry
> SP890 Canadian Aluminum
> Any cylinder manufactured from 6351-T6 aluminum

Are there any exceptions to your cylinder qualification requirements?

We fill the small cylinders used in Buddy and Drager rebreathers. Although these cylinders lack a TC/DOT stamp, we fill them to a maximum of 200-Bar (3000 psi) if they have a current evidence of visual inspection sticker.

Will you fill a scuba cylinder over 15 years old?

Yes. As of Winter 2002, if it meets all our other cylinder qualification requirements, we will fill any scuba cylinder regardless of its age or composition.

How do I know if my aluminum cylinder is made from the 6351-T6 alloy?

As a general rule, you should suspect any aluminum scuba cylinder manufactured in the US before 1990 was made from the 6351-T6 alloy. However, different manufacturers ceased using the alloy for production of scuba cylinders at different times, so the general rule is not precise. Luxfer phased 6351-T6 out over two years and had completely ceased using it by mid-1988. Walter-Kidde ceased SCUBA cylinder production using 6351-T6 in 1989, and Catalina never used 6351-T6. In 1994, the US Department of Transportation (DOT) issued a Safety Advisory Notice #94-7 which identified in detail most 6351-T6 alloy cylinders (including many non-scuba cylinders) manufactured in the US. In 1999, the DOT issued a follow-up Safety Advisory Notice #99-11 which reiterated and supplemented precautions regarding 6351-T6 alloy cylinders. You should consult these notices to precisely determine which cylinders are made of from the 6351-T6 alloy.
DOT SP6498
DOT E6498; E7042; E8107; E7235; E8023; E8115; E8364; E8422.

See Ontario Fire Marshal (OFM) And The National Institute For Occupational Safety and Health.

Cylinder Contents FAQ

What is the quality of your breathing air gases?

Our gases are analyzed quarterly by an independent laboratory to ensure that our breathing gases meet ultra-pure standards for carbon monoxide, methane, moisture, oil, particulates, and odour. Our compressors incorporate a variety of filter systems that allows us to produce and store gases that meet what is known as the Grade E quality verification level as defined by the Compressed Gas Association (CGA) in 1997. At our fill station, just prior to our fill whips, we have a special final filter system which allows us to deliver gases that meet an even more stringent purity specification known as oxygen-compatible (OCA) as defined by IANTD through 2007.

How can I be certain about my cylinder contents?

We have a simple but effective system to assure you know what is in your cylinder. You must complete a work order tag placed on the cylinder to indicate the desired final contents and pressure. The work order tag provides the fill station operator with a clear visual indication of what gas to put in the cylinder. Once the cylinder is filled, we assist you in performing an analysis of the cylinder contents in your presence. Finally, we affix a strip of non-residue adhesive “tank tape” marked with the actual contents and MOD.

What cylinder content labels do you recommend?

Unlabeled cylinders are assumed to contain air. For cylinders containing a gas other than air, our recommendations differ depending upon the intended use and type of gas.

In sport diving, we recommend (but do not require) cylinders containing nitrox with oxygen concentrations of 40% or less should be labeled with a colour-coded, 6-inch-wide band. The top 1 inch and the bottom 1 inch of the band should be yellow. The middle of the band should be green with the word nitrox in yellow.

In technical diving, the cylinder labeling has become somewhat controversial, with some training agencies specifically recommending against contents labeling, and others requiring contents labeling. If you choose to label your cylinders, we recommend the following:

> Cylinders containing nitrox less than or equal to 40% should be labeled with the words  “nitrox” or “breathing gas other than air”
> Cylinders containing nitrox between 41% and 74% should be labeled with the words “decompression mix” or “breathing gas other than air”
> Cylinders containing oxygen concentrations of 75% or greater should be labeled with the word “0xygen”
> Cylinders containing trimix should be labeled with the word “trimix” or “breathing gas other than air”
> Cylinders containing Argon should be labeled with the word “argon” AND the words “DO NOT BREATHE”

All cylinders containing a breathing gas other than air should have a label or tag indicating the oxygen percentage currently in the cylinder and the maximum operating depth (MOD). In addition, cylinders containing mixtures with MODs less than 100 feet should have the MOD marked in 3-inch-high numbers such that the MOD is clearly visible during the dive.

What cylinder content labels do you require?

We think labels and stickers on scuba cylinders are in some ways counter productive because they encourage and obscure corrosion. We require all cylinders containing a breathing gas other than air to have a label or tag indicating the oxygen percentage currently in the cylinder and the maximum operating depth (MOD). We require argon cylinders to be clearly marked with the words “DO NOT BREATHE”.