I don't see the value in permanently marking a tank or choosing one mix for every dive. You plan a dive, choose the best mix, request the mix, analyze the mix, label it and dive your plan, repeat. If you can't get partial pressure blends where you dive you do the same aforementioned procedure except when planning your dive you choose a banked mix that doesn't exceed 1.4 ppo2. That's it. If you don't trust the operations analyzer then buy your own to double check for discrepancies. Cootwo from DiveNav seems like a solid option.
I don't want to derail the thread too much, but I do have a question for the board. What are your thoughts on permanently marking a bailout or pony bottle and using enriched air? Being that this tank is likely not going to be drained and filled over the course of several dives or even months of diving I can see some pre planning being implemented to have a more permanent approach. If I recall, I've read some people recommend only air in a bailout bottle, but let's say where you dive ranges from 60-100 feet with a hard bottom, does anyone see an issue with filling your tank with a mix of say 32%? This keeps you well below 1.4 ppo2 which I think is advantageous considering if you're going to your bailout you're probably exerting more effort and increasing the possibility of an ox tox. Also, if you've done some rock bottom calculations so your carrying the appropriate sized cylinder and can actually make a typical ascent with stops and you're typically a repetitive dive diver the extra O2 may offer some help to prevent lower level/sub clinical DCS. Honestly, I don't know how much of a difference 32% would make over 21% in that regard, so I'd like to hear more.
