FAQ ABOUT REBREATHERS
Open circuit divers considering transitioning to closed circuit diving need basic information about rebreather equipment and safety, course descriptions, costs and logistics. Without getting bogged down in too much detail, the best place to start may be to read our article Closed-Circuit Rebreather Instruction.
The Analytical brand sensors are sealed in a plastic bag inside a cardboard box, while the NRC brand sensors are suspended in a cardboard sleeve and sealed in a metal "pop-top" can. The Analytical brand sensors have an expiration date clearly printed on the label. The NRC brand sensors have a week and year of manufacture encoded as the last four digits of the product number that appears below the barcode on the label. The Analytical brand sensors are manufactured in the US, while the NRC brand sensors are manufactured in Germany. Our inventory of both brands are of recent manufacture, directly from their respective factories. There are also insignificant minor differences in the technical specifications between similar models for the Analytical brand and NRC brand oxygen sensors.
Historically, some rebreather divers express a preference for a specific brand oxygen sensor, however in our opinion both Analytical and NRC brands are very good quality and perform equally well in practice. We are currently offering both brands of the most popular R-22D and R-17D compatible models in order to enhance our supply chain availability for oxygen sensors during the global pandemic.
Yes, Sofnolime™ 8-12 Mesh NI (Grade 797) is currently the best granular option for your Dive Rite O2ptima, Poseidon VI or Se7en, and rEvo CCRs.
The Dive Rite models with the 2015 packable/EAC scrubber can accept either granular or Extendaire cartridge, earlier versions can only accept the Extendaire cartridge. The Poseidon models originally used a Molecular cartridge that is no longer available, and now require a self packable granular adapter. The rEvo only accepts granular for the self packable cassettes used in its dual scrubber system.
The primary difference today from the user standpoint is that the Poseidon Se7en+ electronics module has been updated to include native support for Poseidon's optional Solid State Oxygen Sensor. Due to improvements in gas injection the Se7en+ design now requires three instead of four solenoids, theoretically improving reliability by reducing parts count. There also are some internal differences that make the e-module easier to manufacture, assemble and service at the factory. Support for granular absorbent (in the form of a self-pack cartridge) is also now included as standard on the Se7en+ model, as the pre-pack cartridge has been discontinued.
The digital solid state oxygen sensor (SSO2) is not a plug compatible replacement for the analog oxygen sensor and so currently only Poseidon devices can use the SSO2. To adapt the SSO2 to other brands of rebreathers would need a method to physically plumb the SSO2 in to the loop for monitoring using the Poseidon M28 dive computer, or a major revision to the rebreather controller electronics. For obvious reasons, Poseidon is not in a position to modify other brands of rebreathers. However, Poseidon is actively promoting their SSO2 technology to other rebreather manufacturers and we are aware that several rebreather manufacturers are looking at methods to provide one or the other solution, or both, as options.