CCR Instruction for the Dive Rite O2ptima and Poseidon Se7en rebreathers.

Dive Gear Express offers instruction at our facility in SE Florida for all models we sell. Below is general information on rebreathers, transitioning to closed circuit diving, rebreather safety, course descriptions, prices, and logistics, plus an equipment list for rebreather training. Much of the content of this web page is authored by our staff senior rebreather instructor Mark Derrick:

About Mark Derrick, IANTD Rebreather Instructor


A certified SCUBA diver since the early 70's, Mark Derrick is a long time technical diving instructor originally from North Alabama. Earning his first rebreather instructor rating in the late 90's, in 2000 he retired from the information technology sector, moved to Florida and focused on diving and technical instructing. Mark eventually ceased all his open circuit diving to focus exclusively on closed circuit rebreather diving. While he is an active rebreather technical diver, choosing to dive closed circuit exclusively Mark has not performed an open circuit dive since 2005. In 2017 Mark was appointed to the International Association of Nitrox and Technical Divers Board of Advisers, and Mark is member of the Diver Death Review Committee - University of Florida as a specialist in rebreather forensics. Now based in Pompano Beach Florida, Mark is an IANTD sport and technical CCR diving instructor for several different model rebreathers, currently the Dive Rite O2ptima and the Poseidon Se7en.

Rebreather Diver

Some Rebreather Vocabulary

A SCUBA device that allows you to recycle what you breathe over and over again is called a rebreather. Your body burns the oxygen you inhale then you exhale the carbon dioxide waste, so a rebreather does the following:

  • Captures and recirculates the gas you are breathing with a breathing loop.
  • Purifies the gas to remove carbon dioxide with a process called scrubbing.
  • Refreshes the breathing gas by adding replacement oxygen gas.
  • Compensates for reducing loop volume during descent by adding inert diluent gas.

There are a variety of designs for rebreathers and their components. For recreational diving the most popular type of rebreather has become the fully closed-circuit breathing loop and is often referred to as a CCR. The loop uses counterlungs to store the gas when you exhale and to supply the gas when you inhale. Also part of the loop is a scrubber canister, which contains chemicals to act as a carbon dioxide absorbent. As the oxygen in the loop is consumed by the diver, the CCR replaces it to maintain a constant level of oxygen known as the PO2 set point.

The rebreather set point can be controlled using either manual or automatic systems. There are lower cost manual only rebreathers (mCCR) where the diver is responsible for monitoring the breathing loop via oxygen sensors and operating a valve to manually adjust the oxygen level. The most popular closed-circuit rebreather design today is capable of both manual and/or electronic (eCCR) operation. (Both the Dive Rite and Poseidon rebreathers are eCCR types.) The eCCR uses a small battery powered computer to continuously monitor the oxygen sensors and automatically control a solenoid valve to adjust the amount of oxygen.

Deciding to Switch to Closed Circuit

CCR is a reasonable choice for any active diver who is looking at CCR as a new learning opportunity and personal accomplishment. If you are early in your project of researching the idea of diving with a rebreather, you could start by reading Basics of Rebreather Diving by Jill Heinerth. In reality, the information you need to make a decision is pretty straightforward.

Key Advantages of Rebreathers

  • Silence - The closed-circuit rebreather produces almost no bubbles and the resulting silence enhances the dive in part because the marine life are not alarmed by the diver. If you are a photographer, the silence of the CCR will make huge improvement in your marine life interactions and photo opportunities.
  • Extended Ranges for Depth and Time - The CCR carries hours of breathing gas regardless of depth, so diving time is no longer limited by the size of the tank. A rebreather can also greatly extend the no decompression time limits (NDL's) for sport divers. If you are a technical diver or overhead environment diver, then almost certainly a CCR makes sense.

Key Disadvantages

  • High Cost - There is a wide price range, but the cost to become an eCCR diver is typically many times that of an open-circuit diver. Consumables in remote destinations can also be costly to obtain.
  • Complexity - The rebreather being more complex means additional time spent on logistics and equipment maintenance. Rebreather divers must always plan ahead to assure availability of absorbent and oxygen.

Another way of analyzing the CCR decision is to ask yourself "Am I able to do the dives I want on open-circuit?" If the answer is "No" because your diving has reached a limitation that a rebreather could overcome, then it is time to consider becoming a closed-circuit rebreather diver.

What Rebreather Should I Buy?

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. Beyond the features of the rebreather itself, you should consider model design goals and quality of support. Keep in mind when talking to CCR divers and even CCR instructors, you can hear some strongly biased opinions regarding specific rebreathers and what might be right for them may not be appropriate for you.

In addition to the Dive Rite O2ptima (Shearwater electronics) and Poseidon Se7en (G7 electronics + M28 if for tec), there are other good eCCR choices with the Innerspace Megalodon (Apecs4 electronics), Mares rEvo (Shearwater electronics), and AP Diving Inspiration (Vision electronics). Divers on a tight budget might consider the mCCR designs from KISS. We think divers new to rebreathers would do well to select from this "2018 short-list" for first time buyers, although there are many other good choices and this list should not be construed as a recommendation or disparagement of any specific unit.

The Dive Rite O2ptima and the Poseidon Se7en are both richly featured and proven designs with good redundancy from well established manufacturers. The Poseidon is a European design that favors the sport diver with intentions of continuing on to technical diving, and offers some of the most advanced technology in the market. The Dive Rite is a North American design that favors the technical diver already doing physical overhead or planned decompression dives. Both units are robust eCCR choices that will take you as far as you wish to go in general sport and technical diving.

If you are uncertain about your selection, a carefully supervised confined-water 'rebreather experience' might help with narrowing your choice and Dive Gear Express is happy to organize a private pool trial. Like automobiles, once you have selected a specific rebreather there are still several configuration options to determine the final unit to be delivered. Our experienced rebreather staff at Dive Gear Express stand ready to advise you on the various options, but the detailed FAQs below will answer many of your questions about the specific models we sell:

Click Here to read Dive Rite O2ptima FAQ by Mark Derrick.

Click Here to read Poseidon Se7en FAQ by Mark Derrick.

Perhaps the most important decision you will make is not the brand or configuration of your rebreather, instead the most critical decision you will make is choosing your instructor.

Why You Need Rebreather Training

Every rebreather has unique model specific training, logistics, consumables and maintenance requirements. Even certification to dive a Poseidon Se7en will not qualify you to dive a Dive Rite O2ptima, and vice versa. A dangerous preconception we sometimes encounter is that diving closed-circuit is just another "rung on the ladder" in the dive training flow chart and certification is a mere formality for highly experienced open-circuit divers. That preconception is simply not true for rebreather diving. A famous case illustrating the importance of training is the fatality of a well known underwater cinematographer with exceptional open-circuit diving experience who died while diving untrained on a borrowed rebreather. Just to be clear, NO amount of open-circuit training or open-circuit experience will enable to you to competently and safely dive on closed-circuit rebreathers. 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.

Closed-Circuit Rebreather Training Course Summaries and Prices

We offer several different training entry points toward a certification as a rebreather diver, each with different prerequisites, information, skills and limits:

  • Unit Update or Refresher - Both Dive Rite and Poseidon have released major electronics upgrades and optional back mounted counter lungs. Although there is no official certification required for updates to your existing O2ptima or Se7en, they are significant changes that do require new skills or modification to your existing skills. Perhaps it's just been a while since you have been in the water with your rebreather and would like to refresh your CCR diving skills. The content of an instructor supervised review can be tailored to the diver's prior training and experience, contact us to discuss your specific goals.
  • CCR Crossovers (Dive Rite or Poseidon) - These fast paced programs are for experienced and active CCR divers who wish to cross-train for certification on the Dive Rite or Poseidon unit. The training time is approximately two days (often three depending on logistics) consisting of assembly review, a confined water session and two open water dives. Price for instruction and training materials is $599.00; price does not include CCR consumables, equipment rental or boat trip. For divers who have not been on a rebreather recently or who have a small number of total hours on rebreather, we suggest taking a full CCR course instead of a crossover. If you are an SCR diver, we recommend one of the full CCR courses.
  • CCR Recreational Diver (Dive Rite or Poseidon) - This is most like an entry level open water course, except instead of being for open-circuit, the diver is trained to use a closed-circuit rebreather. All dives are limited to no-stop required not exceeding { 70 fsw | 21 msw} deep. The training time is approximately three to four days including four open water dives. Price for instruction and training materials is $749.00; price does not include CCR consumables, equipment rentals or boat trips.
  • CCR Recreational Mixed Gas Diver (Dive Rite or Poseidon) - This course is the entry point for experienced open-circuit divers who expect to remain within sport diving limits doing CCR no-stop required dives no deeper than { 132 fsw | 40 msw}. The training time is approximately four to five days including six open water dives. There is a version of this same course ("CCR Recreational Deep Diver") for Air diluent only divers, but we generally recommend the Mixed Gas version 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, better work of breathing, and improved scrubber function. Price for instruction and training materials is $999.00; price does not include CCR consumables, equipment rentals or boat trips.
  • CCR Diver (Dive Rite or Poseidon) - This skills intensive course is the entry point for all open-circuit divers with prior training in required-stop decompression diving. We teach this course with a 15 minute maximum of planned decompression and { 170 fsw | 51 msw } maximum depth. The emphasis in this course is on diagnosing and solving CCR problems in order to remain on the rebreather loop whenever possible. The training time is approximately five to seven days including extended classroom lectures and a minimum of six (usually eight) open water dives. This is nothing like a 'basic open water' recreational course, you will have 500+ minutes of time on the rebreather by the end of your training. Price for instruction and training materials is $1499.00; price does not include CCR consumables, equipment rentals or boat trips.
  • CCR Technical Diver Programs - We offer a progression of CCR training programs to qualify divers for depths up to {330 fsw | 100 msw} and beyond. Some of the experience of open circuit technical diving will carry over to CCR but the logistics, gas planning and survival skills required for CCR technical diving are very different than those of open circuit. These courses do not include any unit specific content, so even highly experienced open-circuit technical divers must first complete a unit specific course, and then build a minimum of 50 hours on that unit before entering these courses. Courses are tailored to the diver's prior training and experience, contact us to discuss your specific goals.

The course descriptions represent the minimum training requirements and we always try to provide additional education and learning opportunities whenever training standards and logistics allow. Training course content and length varies as appropriate, but all the CCR courses as taught at Dive Gear Express have similar structure and elements: facilities orientation, prerequisites and standards review, safety discussion, hands-on detailed assembly and configuration of rebreather, classroom lecture, confined water (pool) equipment skills session, pre-dive trip briefings, rebreather setups using a checklist, half-day dive boat trips, open water skills and drills, post-dive trip debriefings, written examination, exit interview. As with any SCUBA course, training is purchased but certification is earned only when the student and instructor are both in agreement the training requirements have been completed to their mutual satisfaction.

Your Rebreather Training at Dive Gear Express


Dive Gear Express is a long time member in-good-standing of the International Association of Nitrox and Technical Divers as a Platinum Premier IANTD Full Service Technical Facility. Training is normally done right here at our fully equipped facility in Pompano Beach, Florida USA. The logistics for rebreather diving are extremely good. Our facility has a comfortable classroom, meticulously maintained mixed gas and oxygen fill station, convenient work space for CCR setup and tear-down, extensive stock of consumables and spares, as well as on-staff equipment repair technicians. The water conditions are excellent year round (low 70's in the winter and low 80's in the summer) and the range of dives offer you a nice bit of experience (shallow and deep reef, shallow and deep wreck) to learn on your rebreather. On-site training at your choice of any global location with appropriate logistics is also available; we've organized training aboard yachts and at resort destinations all over the world.

The calendar schedule varies depending on your requirements, but course openings are available most weeks of the year. Keep in mind that finishing on-time assumes we will be able to dive without interruption from logistics or weather. We find many divers prefer a slower pace, and we are happy to accommodate. The reality is needing an extra day is not unusual, and we recommend planning for an extra day or two. If the extra time is not needed then it allows additional diving immediately following course completion to help reinforce your new skills. Send us some date ranges that work for you and we will reply with some specific choices of availability.

Travelling students can stay at the Sands Harbor Hotel (about 3 out of 5 stars) because it is conveniently located and economically priced; be sure to ask for the "ScubaTyme" discount. However, there are a wide range of private and chain hotels in Pompano Beach, the choice is entirely yours. You also will benefit from having a rental car during your stay or you can use a ride-share service such as Uber or Lyft.

There is a liability and assumption of risk waiver that you must read before class. There is also a form that contains a few questions about your health. If you answer "YES" to any of the questions, depending on the circumstances you may be required to have a doctor's letter that clears you for scuba diving activities. If you are currently a smoker, we require you to refrain from smoking for 24 hours prior to any in-water activities on the rebreather.

In preparation for the course, we ask you to read the following, PRIOR to attending the first day of class:

  • Rebreathers Simplfied Revision 4 by Dr. Mel Clark. Although not a formal requirement of the training standard, this text is very useful in providing us with a common vocabulary, and also offers a great review of basic physics and physiology particularly as it applies to rebreathers. This will save time in the classroom lecture, allowing that time to be spent gaining a deeper understanding of rebreathers. If you do not already have a copy of this manual, you may order it from the Dive Gear Express website.
  • The manufacturer supplied user manual for your specific model rebreather. The primary goal for reading prior to class is that you can identify major sub-assemblies, key components and their functions - especially how to read and interpret the electronics. Don't worry too much about the specifics of the checklists at this point, you will review that content iduring class. The current version can be downloaded from the website of the manufacturer for your specific model rebreather:

  • For the courses with planned required-stop decompression, please read IANTD Tek CCR, second edition. Some of the contents in this manual are repetitions of material that is explained in previous documents. However, you will discover a very different perspective on some topics and most people find the two texts to be complementary. The two chapters on Oxygen and Carbon Dioxide by David Sawatzky will give you a very good understanding of these two critical aspects of rebreather functionality. If you do not already have a copy of this manual, you may order it from the Dive Gear Express website.

Keep in mind that helping you to understand the material and answer your questions is a key part of the job of your instructor. We look forward to seeing you in class.

Equipment You Will Need for the CCR Diver Course at Dive Gear Express

Obviously, you will need a Dive Rite or Poseidon rebreather with BCD and harness. If you purchased your rebreather from other than Dive Gear Express, most students arrange to ship their rebreather ahead to our offices in Pompano Beach. If you purchased your rebreather used, we recommend that it receive a factory overhaul service prior to the course. We can also supply Dive Rite or Poseidon units for rental during our courses. Other equipment you will need to bring:

  • You will need a wet or semi-dry neoprene exposure suit, 3mil or 5mil in the summer, 5mil or 7mil in the winter, or you can use a dry suit. A full hood, even if just nylon, and tropical style dive gloves are a good idea and recommended.
  • You will need technical style diving fins with boots . A spring heel strap design is strongly recommended.
  • You will need a low volume dive mask that fits well without having to frequently clear it. A key feature of the mask is that you will need to be able to clearly see the heads up display mounted on your rebreather, this implies that you will need a 'tear drop' style lens with a large look down field of vision.
  • You will need a surface marking buoy (SMB) along with a safety reel containing ~150 feet of line and a line cutting device.
  • You will need a slate or other writing device. An executive slate or tablet style is best, underwater notepad style works too, but a not wrist slate.
  • For off-board open-circuit bailout, you will need an open-circuit regulator with a 40-inch LP hose plus an SPG with a short HP hose or a button gauge. Technical courses may require multiple regulators and should include hoses with a quick-release fitting that can plug into your breathing loop.
  • For the courses with planned required-stop decompression, you will need a back up depth and time device. A dive computer that offers a constant PO2 mode (aka CCR mode) is recommended. Perhaps best is a redundant decompression and PO2 monitoring package option integrated with your rebreather.
  • Please bring your dive certification cards along with your dive log as well as a photo ID. You will not be able to dive until we can verify your certification and experience meet the prerequisites required for training.

Tanks and weights are supplied as needed as part of the course at no charge, or you can bring your own if you prefer. We have CCR oxygen and diluent cylinder pairs of 2L & 3L aluminums and 2L, 3L & 4L steels, all with your choice of inline or modular valves, plus bailout 30's, 40's and 72's rigged for sidemount. If you bring your own cylinders they must have current VIP, be O2 clean and appropriately labeled. Dive Gear Express has a meticulously maintained fill station with an integrated carbon monoxide detector, and can supply banked OCA grade Nitrox 32 and 21, UHP grade Trimix 21/35, ABO grade Oxygen 100, as well as custom gas blends for technical courses.

You'll also need the usual other non-dive comfort stuff you are in the habit of using in tropical diving... swimsuit, towel, sunblock, sunglasses, etc. In the winter you will want a light jacket with hood or dive parka. If you don't have some item mentioned above, don't worry about it. Other than exposure suits, we have one of the largest inventories of technical dive equipment in Florida.

Ready to dive silent? You can inquire using our Contact Us page and Mark will reply.

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