Hello! New to the forum, researching redundant air options :)

[Bert van den Berg]

If you don't do decompression diving my suggestion is a 19 cu pony. Smaller probably a waste of time, larger gets challenging physically. Your age might have a bearing on your choice. I'm 73 and the 19 cu is very manageable for me. Younger people might feel the same with a 40 cu.

 

[undrwater]

I slung a 40 and a 19 for shore dives with a "soft ceiling" (boat traffic).

For the hike down to the water, I preferred the 19. IN the water, I preferred the 40. It was just more comfortable and easier to manage.

 

[Tripp]

I've only dived at Medina lake and Canyon Lake. Canyon has been slightly clearer. I want to go down to the coast and take the boat dive to the Flower Garden Banks!

 

[tursiops]

The best advice I can give you is to be a team player. Every piece of scuba equipment should adhere to the terminology that dive equipment is life support.

I have no idea how this post relates to the thread.

 

[boulderjohn]

The best advice I can give you is to be a team player. Every piece of scuba equipment should adhere to the terminology that dive equipment is life support.

I have no idea how this post relates to the thread.

This is part of the mystery that is Scuba Client. He was briefly banned, so I assume the staff investigated before reinstating. Back when I was on staff, posts like this were red flags, as I will explain later. I must assume the staff still recognizes that same red flag and investigated.

The first time I remember Scuba Client was in a thread in which a similar event occurred--a post with a vague and hard to understand meaning that was only marginally (at best) on topic. I asked for more information, and I got some replies that were cryptic and evasive but eventually made it clear that he (???) did not know much about the topic. In that thread, Scuba Client was assisted by several members who tried to answer my questions themselves but mostly muddied the waters.

So, the red flag is for a bot, an artificial intelligence computer program that tries to disguise itself as a human being. When I was on staff, our understanding was that programmers would test their bots in various social media, like ScubaBoard. We banned quite a few. I assume something like that was considered by staff this time, and they must have gotten some kind of understanding that this was not the case. It's easy enough to check by sending an email to the user asking for specific information.

Getting back to the first instance, I smelled bot pretty quickly, but the responses to my questions seemed like a genuine human trying to wriggle out of my questions, something I saw countless times in my teaching career when students who didn't know a thing about the topic on a test's essay question tried to write something that would conceal their ignorance and sound reasonable. I also saw some responses from Scuba Client in other threads that actually seemed to be apt.

So, I don't know what to make of most of Scuba Client's posts, and I assume some day an explanation will come.

 

[Angelo Farina]

What follows is just my personal opinion. I own a 3-liters aluminium pony tank, but i did use it only in very extreme diving conditions: very deep (50+ meters), deco planned, in caverns, etc...
I find it very disturbing in terms of agility, being streamlined, etc.. So I possibly used it no more than 10 times in my life.
During the first 10 years of my diving career (when diving deep and with deco was the norm) I instead always use a 10liters+10liters steel twin tank, or a 9l+9l alu twin tank. This is less disturbing, more streamlined - and the twin alu tank brings you perfectly horizontal.
Such twin tanks provide a huge amount of air. They have two posts with independent valves, so you can use two independent regs. At the time there was no separation manifold, but still such a twin tank did provide enough "redundance" fo being safe, without the hassle of a pony tank.
Now, being much older, I do not dive anymore to such depths and with planned deco, so I reduced my need to a single tank.
Still it is a 15 liters steel tank with twin valves and double posts, so i can use two fully-independent regs. And now the pressure is 232 bars instead of 200 bars, so a 15 liters tank still provides a reasonably large amount of air.
I think that for diving at modest depth (no more than 40m) and with no deco obligations, such a 15 liters tank with two separate regs provides enough redundancy for being "safe enough".
However, I would NOT feel safe with a smaller AL80 tank, and with just one valve and one first stage with an octopus. I had seen enough failures of the O-ring on the post, or complete failures of the first stage for considering this setup "not safe enough" for me...
So I agree with you that going beyond that basic setup used by moist recreational divers is a good idea. But I suggest to evaluate alternatives to a pony tank, such as a compact twin tank: now they make these nice 7l+t7l twin tanks at 300 bars, with separation manifold. They are very practical to move around, very streamlined on your back, they have DIN connection which is much safer than yoke, and I think that if I have to buy a new tank nowadays that would be my first choice.
It i just below 500 eur here:
Bi-bombola 7+7L 300b Wide
The other possibility would be a single tank of say, 12 liters at 300 bar or 15 liters at 232 bar. Much cheaper but equipped with a double valve system, it still allows to use two fully independent regs. For recreational diving this would be my "Plan B", if I can't afford the compact twin tank shown above.
The first one is around 400 eur here: BOMBOLA IN ACCIAIO 12 LT EUROCYLINDER CON RUBINETTERIA 300 bar
or the second one, which is what I use now, it costs less than 300 eur: here: Bombola Sub Mares 15 Litri Rubinetteria INT-DIN Biattacco Prod. 2020
Of course the first is more streamlined and compact, but in the end I am currently happy with my 15-liters. And not everywhere then can fill the tank up to 300 bars, instead 232 bar is quite normal everywhere.
It must be said that renting a 15-liters at 232 bars is absolutely common here in the Mediterranean sea, and most diving centers have dual-valve tanks. I understand that in countries where the average depth is shallower and deco is seen as an anomaly such semi-professional tanks are not so common.

 

[jale]

This is part of the mystery that is Scuba Client. He was briefly banned, so I assume the staff investigated before reinstating. Back when I was on staff, posts like this were red flags, as I will explain later. I must assume the staff still recognizes that same red flag and investigated.

The first time I remember Scuba Client was in a thread in which a similar event occurred--a post with a vague and hard to understand meaning that was only marginally (at best) on topic. I asked for more information, and I got some replies that were cryptic and evasive but eventually made it clear that he (???) did not know much about the topic. In that thread, Scuba Client was assisted by several members who tried to answer my questions themselves but mostly muddied the waters.

So, the red flag is for a bot, an artificial intelligence computer program that tries to disguise itself as a human being. When I was on staff, our understanding was that programmers would test their bots in various social media, like ScubaBoard. We banned quite a few. I assume something like that was considered by staff this time, and they must have gotten some kind of understanding that this was not the case. It's easy enough to check by sending an email to the user asking for specific information.

Getting back to the first instance, I smelled bot pretty quickly, but the responses to my questions seemed like a genuine human trying to wriggle out of my questions, something I saw countless times in my teaching career when students who didn't know a thing about the topic on a test's essay question tried to write something that would conceal their ignorance and sound reasonable. I also saw some responses from Scuba Client in other threads that actually seemed to be apt.

So, I don't know what to make of most of Scuba Client's posts, and I assume some day an explanation will come.

Maybe (s)he is just a "human bot"

 

[scubadada]

Hi @Dan_vG

Do the operators you want to use in the Great Lakes require a redundant gas source for diving with a buddy? If yes, you must do it. If no, folks dive every day within rec limits without a redundant gas supply.

 

[Scuba Client]

This is part of the mystery that is Scuba Client. He was briefly banned, so I assume the staff investigated before reinstating. Back when I was on staff, posts like this were red flags, as I will explain later. I must assume the staff still recognizes that same red flag and investigated.

The first time I remember Scuba Client was in a thread in which a similar event occurred--a post with a vague and hard to understand meaning that was only marginally (at best) on topic. I asked for more information, and I got some replies that were cryptic and evasive but eventually made it clear that he (???) did not know much about the topic. In that thread, Scuba Client was assisted by several members who tried to answer my questions themselves but mostly muddied the waters.

So, the red flag is for a bot, an artificial intelligence computer program that tries to disguise itself as a human being. When I was on staff, our understanding was that programmers would test their bots in various social media, like ScubaBoard. We banned quite a few. I assume something like that was considered by staff this time, and they must have gotten some kind of understanding that this was not the case. It's easy enough to check by sending an email to the user asking for specific information.

Getting back to the first instance, I smelled bot pretty quickly, but the responses to my questions seemed like a genuine human trying to wriggle out of my questions, something I saw countless times in my teaching career when students who didn't know a thing about the topic on a test's essay question tried to write something that would conceal their ignorance and sound reasonable. I also saw some responses from Scuba Client in other threads that actually seemed to be apt.

So, I don't know what to make of most of Scuba Client's posts, and I assume some day an explanation will come.

If you need more evidence of the truth, ask yourself why are you commenting on my threads. Reason, for self promotion and exposure. I have no conflict of interest. I didn't expect you of all people to stoop this low. Scubaboard is about networking; exchanging ideas, without bias or prejudice.

 

[SlugLife]

Hi @Dan_vG

Do the operators you want to use in the Great Lakes require a redundant gas source for diving with a buddy? If yes, you must do it. If no, folks dive every day within rec limits without a redundant gas supply.

I generally don't call required equipment "redundant" even if it technically fits the definition. I see redundant more like the idea of 3-flashlights on a night-dive, and if one failed you could still continue the dive. I'd also see a pony-bottle that was treated as life-insurance-only, where there's a less than 1/1000 chance you might need it, but carry it anyway.

Anyway, I agree. If an operator required a redundant air supply, I'd definitely look at that as BIG warning sign. I'd probably ask why they require it, and how often divers have actually used their redundant supply. Finally, I'd probably opt out of the dive as a rec-diver, even though I have a redundant air supply.