CCR FAQ - O2ptima-2018

Prepared by Mark Derrick, CCR Instructor on Staff

How much does an O2ptima cost?

A better wording of the question might be 'How much does it cost to switch from an open-circuit diver to a rebreather diver?' The price of the rebreather itself can vary significantly depending on configuration options. Plus there are usually additional equipment purchases depending on what existing gear you have that can be re-purposed. Training, particularly if travel is required, will be a significant cost. I suggest planning on a total budget amount of about $15,000.00 maximum.

How long does it take to get an O2ptima rebreather?

O2ptima rebreathers, along with all options, accessories and spares are usually in-stock for immediate shipment. Occasionally, demand or logistics will cause brief stock-outs of the base O2ptima unit but delays beyond 30 days are rare.

How much does the O2ptima training cost?

There is wide variation in training costs due to a variety of factors, although location is often a major influence. There is a geographically diverse group of instructors and you might have an instructor in your local area. Typically, the cost ranges from $1000 to $1500 for instruction only, plus out-of-pocket costs. If you prefer to learn about your rebreather at Dive Gear Express in Pompano Beach Florida, training can be organized to accommodate your schedule and rebreather courses run every month.

Can I buy the rebreather without training?

Yes, but you won't be able to dive the rebreather until you are trained. Every rebreather requires formal, model specific, training in order to competently dive with the equipment; ordinary open-circuit training is not adequate. If you are not already certified for the rebreather, per manufacturer requirements you will receive a disabled unit that can only be enabled by your instructor. Once you complete training, your instructor will permanently enable your unit.

How much does O2ptima routine maintenance cost?

You should budget routine maintenance costs of approximately $500 annually. The manufacturer recommends the canister O-ring set, wiring harness, mushroom valves and four oxygen sensors be replaced annually. They also recommend the first stage regulators be serviced every two years or 100 dives. You will also need to replenish minor consumables such as lubricant and disinfectant from the annual maintenance budget.

What consumables do you recommend for the O2ptima?

The recommended consumables are: Micropore ExtendAir CO2 absorbent cartridge model 101C and/or 8-12 mesh granular absorbent, Steramine for sanitizing the breathing loop, Tribolube 71 O2 Compatible Lubricant for O-ring seals, Caig Labs DeoxIT GOLD for cleaning gold electrical contacts, and Analytical Industries PSR-11-39-MD diving grade oxygen sensors. The Shearwater electronics require two AA size and one 9V size consumer grade batteries such as Energizer or Duracell.

How much do the O2ptima consumables cost?

As with all rebreathers, the major consumable cost is CO2 absorbent. The latest scrubber canister design can accept either a quick load cartridge or a { 5 lb | 2 kg} granular absorbent self pack. A granular absorbent fill is approximately $25 or absorbent cartridge is about $35. Compared to granular, the cartridge costs a little more per hour, but even assuming the cartridge is more expensive than granular, this is justified because the cartridge absorbent offers important and valuable advantages over granular. The choice of granular or cartridge is yours because the O2ptima easily switches between either type of absorbent. An absorbent load can typically can be used for several sport dives, and there are other smaller costs such as batteries and gas fills. Keep in mind that for both open-circuit and rebreather divers, consumables costs are usually insignificant in relationship to the investment in the equipment, training and other diving costs such as boat charters and travel.

How long do the O2ptima consumables last?

For both cartridge or granular absorbents and based on monitoring oxygen consumption, divers with normal CO2 production rates are reporting durations of 4 to 6 hours in { 70 °F | 21 °C } water and battery durations of thirty to fifty hours. The duration in actual use depends upon many factors related to the individual diver, specific dive conditions and particular brands of consumables. These are observations of what experienced O2ptima sport divers are reporting and in no way suggests exceeding manufacturer recommendations or that novices should expect these durations.

Why does the O2ptima accept CO2 absorbent in the form of a cartridge?

The O2ptima rebreather can use the ExtendAir Cartridge CO2 absorbent manufactured by Micropore. ExtendAir cartridges solve many of the problems associated with traditional granular carbon dioxide absorbents. ExtendAir absorbents use the same chemistry as granular absorbents but in the form of easy-to-use cartridges that are quickly loaded into the scrubber canister (even under adverse conditions). The individually sealed cartridges need only be opened immediately prior to use and are date stamped to assure freshness. ExtendAir cartridges eliminate problems of channelling and duration variability associated with granular absorbents because they eliminate both settling and individual differences in canister filling technique. ExtendAir cartridges also eliminate the problem of absorbent dust contamination in the breathing loop. ExtendAir cartridges are more efficient with better work-of-breathing and more consistent performance than self-pack granular absorbent.

Is the O2ptima CO2 absorbent cartridge more expensive than granular?

Compared to granular, the cartridge costs a little more per hour, but even assuming the cartridge is more expensive than granular, this is justified because the cartridge absorbent offers important and valuable advantages over granular. The choice of granular or cartridge is yours because the O2ptima easily switches between either type of absorbent.

What about the possibility of a 'caustic cocktail' with the O2ptima?

Once you are trained, inhaling a mixture of CO2 absorbent and water while diving with an O2ptima is very unlikely. The O2ptima is a modern CCR design that includes several features to manage and remove water from the breathing loop. If you choose to use the O2ptima cartridge, you eliminate granular absorbent dust contamination, even further diminishing the risks. The 'caustic cocktail' is a concern from an earlier era of rebreather diving that has been overly dramatized, akin to the concern new divers express regarding 'shark attack'.

How available is CO2 absorbent for the O2ptima?

In the global economy, absorbents are sold and shipped all over the world. As a result, supply logistics for absorbent is becoming less of an issue. The number of dive shops that stock absorbent is consistently growing, and you can always order on-line to be delivered to your door or directly to your travel destination. The O2ptima is able to accept both granular and cartridge form absorbents, making the O2ptima exceptionally flexible for absorbent load. Unlike granular absorbents, transport of the cartridge does not raise hazmat objections by carriers and often costs less to ship.

Does the O2ptima have a CO2 monitor?

No. CO2 monitoring is a 'bleeding edge' technology that will begin to appear in recreational rebreathers in the next few years but as a practical matter the merits of CO2 monitoring are unproven. You should not confuse a CO2 monitor with the breathing loop temperature monitor or the scrubber temperature monitor offered by rebreather manufacturers. The temperature monitor does not provide any information or warning regarding actual CO2 levels in the breathing loop.

Does the O2ptima support an external PO2 monitor and backup dive computer ?

We offer a HUD upgrade to provide a Shearwater NERD2 full dive computer rather than the LED display or can deliver your O2ptima with a factory installed external PO2 monitoring cable for an optional Fischer 103 connector compatible wrist mount CCR dive computer such as the Shearwater Petrel-EXT. The additional dive computer provides independent redundant monitoring of PO2, as well as redundant depth/time and decompression status.

What cylinders should I use with the O2ptima?

The O2ptima will accept a variety of cylinder sizes using standard left and right modular DIN valves. Including the valve, the maximum cylinder dimensions are { 18.5 in | 46.99 cm } in length by { 5.5 in | 13.97 cm } in diameter. The O2ptima comes standard with aluminum 20 cubic foot (3L) cylinders. With the volume of the AL-20 cylinder, diluent capacity is sufficient to support on-board bailout for the sport diver (although I do not recommend bailing out to on-board diluent), and provides plenty of oxygen capacity even with transfer under filling. For O2ptima "Sport" configurations I suggest aluminum 13 cubic foot (2L) capacity cylinders, which minimizes the O2ptima total weight. The 13's are more than adequate to support over four hours of sport diving, but with the 13's you should carry an external bailout. Some cold water drysuit divers prefer the additional weight of steel LP27 (4L) cylinders.

Which style of counterlungs should I choose?

Over-The-Shoulder (OTS) vs. Back-Mounted (BMCL) counterlung configurations have subtle trade offs of one benefit for another, and the choice is more complex than can be answered briefly. Conventional wisdom says, all other factors being equal and in most circumstances, over-the-shoulder offers better work-of-breathing than back-mount although the very short breathing loop of the O2ptima BMCL minimizes WOB regardless of type of counterlung. Many professional photographers have a preference for BMCL, but for deep technical diving where performance is paramount some experienced CCR divers would recommend a classic OTS and DSV configuration.

What BC should I use with the O2ptima?

Use whatever harness, backplate and wing style system you prefer that mounts using standard 11-inch centers. We recommend the very comfortable Dive Rite TransPac, adding ring bungees to sidemount your bailout. The Dive Rite CCR Wing has a shape and features that work well with the O2ptima and offers very low drag. The CCR wing offers { 50 lb | 22.68 kg } of lift and technical divers should consider the redundant bladder option. The CCR Wing when supplied with the O2ptima has two pockets added for up to 10 pounds of trim weight and a trim pillow for body positioning.

What about a Bail-Out-Valve (BOV) option for the O2ptima?

The Dive Rite BMCL design depends on the manual additions built in to DiveSoft BOV, but a high-performance DSV only design with OTS counterlungs and manual additions is also available as the O2ptima Classic. BOV's offer benefits especially for new CCR divers, but some experienced CCR divers consider them to be counter productive in technical diving by adding complexity and degrading performance. Regardless, divers should always carry off-board bailout.

What is the O2ptima maximum dive time and depth?

Rebreathers carry many hours of breathing gas regardless of depth. The O2ptima can accept auxiliary outboard plug-in gas supplies as well, so dive time is no longer limited by gas volume. As with most rebreathers, the O2ptima diver is typically limited by the duration of the CO2 absorbent, so multi-hour runtime dives are routine. As with open-circuit nitrox diving, rebreather divers must also track their decompression and oxygen exposure; depending on the dive profile these may also limit the dive time. The O2ptima rebreathers are suitable for diving at all sport depths and have been tested to a depth exceeding 300 feet. There are some individuals who routinely dive the unit that deep and deeper. Although the rebreather can function at depths much deeper, there are numerous additional considerations. The O2ptima rebreather is a popular choice for divers who wish to dive to extremes.

Is the O2ptima capable of diving with mixed gases?

Yes, the O2ptima as delivered can use either nitrox or trimix diluents that may be either hyperoxic, normoxic or hypoxic. Because the O2ptima is a fully closed-circuit design, the use of mixed gas diluents is very inexpensive compared to open-circuit. Personally, I recommend and teach rebreather divers to substitute normoxic trimix diluent (21% oxygen, 35% helium) rather than air even within recreational sport limits for the benefits of reduced narcosis, improved work of breathing, and improved scrubber function. However, use of anything other than normoxic diluent or diving outside of recreational sport diving limits requires significant additional diver training.

Does the O2ptima take a long time to maintain?

Yes and No. Many rebreather sport divers, including O2ptima divers, find they spend noticeably more time on equipment compared to open-circuit because the rebreather diver must always be careful and disciplined about maintenance. However, compared to most other rebreathers the O2ptima takes less time to setup, in part because of the cartridge. If you have been habitually careful with your open-circuit dive equipment and treat your equipment with respect, as an experienced O2ptima sport diver you will spend only slightly more time with your O2ptima maintenance than you did with open-circuit.

How well does the O2ptima travel?

The O2ptima is one of the most travel convenient rebreathers available. A key design goal was to minimize size/weight and divers are able to travel by air with the O2ptima as carry-on luggage in most circumstances. Regardless of the brand of rebreather it can be annoying to travel with cylinders because they are carefully examined by security personnel, and occasionally even confiscated. You may prefer to rent cylinders at the destination or ship the cylinders ahead by a package carrier such as UPS or DHL.

How is an O2ptima different from other rebreathers?

All of the major rebreather models are good quality units. There is no perfect rebreather; they all have strengths and weaknesses that make each uniquely more or less suited to your needs. The Dive Rite O2ptima is a richly featured and proven design with good redundancy from a well established manufacturer. The O2ptima is a North American design that favors the technical diver already doing physical overhead or planned decompression dives and a robust eCCR choice that will take you as far as you wish to go in general sport and technical diving. As an independent dealer, we stock O2ptima spares and consumables with online ordering and same day shipping.

Is the O2ptima rebreather safe?

No type of rebreather can be said to be categorically safer than another. No rebreather is foolproof, and the fact remains that compared to open circuit there is a disproportionate number of rebreather fatalities, many of which have been attributed to diver error. The quality of training may be the most significant factor affecting rebreather safety. Your safety while diving is controlled by you, not by your rebreather.

Last Updated: May-2018

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