Stefan, your comments throughout this have been really engaging, thanks for sharing all that!
And once again, thanks to everyone who dared to share their thoughts!
My O2 cents: (IMHO, with the usual disclaimer of being an Rebreather virgin) I do believe that the canister is too expensive and is not likely to come down in price, DT’s assessment of the situation seems likely correct: “ExtendAir makes money off big contracts (gas anesthesia machines right?) and the scuba market is small in comparison (to the medical market?!)”. if it was a matter of 25% more per hour of operation compared to the average granular scrubber it would not be a big deal, but by my calculations it is a lot more than that ($29/cartridge for 2, maybe three hours of cold water current diving). Stefan’s idea of rating a scrubber with a range of breathing rates and depths sound like it makes a lot of sense. I am one of those people who asks what happens in those cases where people pass out… what unusual circumstances led to that and how can I factor in the worst case scenario to avoid such an unwelcome outcome. The close call I experienced on OC many years ago put a lot in perspective for me. My Atomic B2 allows me to breathe with relative ease at equivalent resp. rate to being at a full sprint… I chose it because there was one time that I was at 120 fsw in a strong down welling, with my life flashing before my eyes it was all I could do to resist the current, with both hands clawing at the sand, my old regulator that I was using at the time breathed like a thin straw that was threatening to implode… the nitrogen and resistance on breathing caused a rush of adrenaline spiraling my cardiac/resp. rate upwards uncontrollably… I even got that subconscious reptilian urge to clear my air passage…gulp!
With the cartridge, or any scrubber, I want to know what it’s capabilities are not just in overall burn time. Under what depth/temperature/resp. rate will the lack of dwell time likely overwhelm it’s ability to “scrub”. Why not do tests in the full range of temperatures and depths encountered by divers: say 35f, 55f and 85f and at three depths each, say 66fsw, 165fsw and 297fsw with relatively high Co2 production with a period of balls out huffing….testing for brief spikes in break through co2. how expensive could this really be, or is it that MFG's are afraid they won't measure up? Then we could each calculate our own comfort zone based on the most like conditions to what we are setting out to do rather than having to play mind games with ourselves about weather we are being conservative enough or not. And on top of that, I’d let the MFG’s off the hook by accepting a clause, like, “this is an estimation based on controlled conditions in a lab, it is impossible to accurately predict the metabolic variations of each user under varying degrees of physical and emotional stress, actual performance may vary, use at your own risk.”
One of the dive rite guys told me over the phone that they had one guy forget to change out the cartridge in between dives and ended up putting 10 hrs on one!! And supposedly “felt just a little funny” at the end of the last dive. Ok, so where does that leave those of us who just think 2-3 hours might be too conservative…Guinea pigs?! If two hours is really the safe limit for the dives I do then no way, I’m out, if 4 hrs is the limit, well then I’m back in the conversation…and if I can dry out or freeze the canister and conserve an unused portion for a week, for those one time after work dives, well then that could tip the scale too. It’s not just a matter of being cheap, I hate being excessively wasteful and I hate feeling like a corporate hore. And of course, if I could choose the cartridge or the granules depending on the application, then I’d be less reluctant to buy the unit.
Rumor has it that the adapter for granules on the optima is coming out in march…I’m not holding my breath, but if it doesn’t come out by the time my excitement to dive bubbleless overwhelms my reluctance to spend 5-10 grand, I may just go for another unit, ironically maybe even a more expensive one like the meg (again, that value calculation is a series of ratios for me…a used inspo or a fully loaded meg are see sawing (the trouble is that my wife wants one too, ahh we can put off having kids and buying that house for a few years can’t we honey?...but really, how can I complain, she’s my dream come true in more ways than one!
).
I’ve heard one shop owner make the mistake of assessing the situation this way…”hey, if your buying a Cadillac then you’re not someone who is worried about saving a few bucks”, and thus he did not think the cost of the cartridge was a big deal. That philosophy starts to mince words…the optima has been promoted as more economically priced eCCR and in any case, some of us sport divers (and apparently sport divers are part of the market the optima is aimed at) who are thinking hard about the long term financial impact buying a rebreather it going to have on our lives are likely to be put off by excessive running cost. Overall value is the deal breaker for all of us isn’t it. I’m guessing there are a lot of folks making the CCR switch who are not rich, but rather water babies who are compelled to make necessary sacrifices to be able to spend a lot more time under water actually exploring what they love.
I was told rather frankly that Micro pore was being given exclusive access to the optima for the first few months to give it a chance to catch on before the granular adapter was released. I spoke to a guy who had the adapter sitting on his desk…word is that it will cost about $200 and is made of stainless steel. Ok dive rite, lay it on the table…and with a solid rating too!