Steel HP 23 vs Al 19 redundant air source

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apenland01

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Messages
262
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Location
Tucson AZ
# of dives
25 - 49
I'm debating between these two choices for a backmount pony mounted on the right side of the main tank upside down with a left mount valve and 40" hose run under the right arm. Main gas is HP100. Diving 90' or less in all cases.

The steel 23 would provide a bit more air than the 19, but be slightly more negatively buoyant at -2.64 full and -0.66 empty. I would most likely counter this with 2lb trim weight on the left shoulder strap to counter potential rolling to the right.

The aluminum 19 is a bit shorter height wise (2" shorter) and more buoyant at -1.7 full and -0.3 empty. Not significant, but something to consider.

Land weight is irrelevant, as I'll be loading these from my truck straight to the boat.

I'm leaning to the steel HP 23.
 
The empty buoyancy is almost a red herring. You wouldn't normally dip into your redundant air source (although I have occasionally pushed consumption on the main tank and counted on the pony for safety stop/ascent).

For the sizes you proposed, the steel 23 tank is 2 lbs heavier but carries >20% more air than alum 19. That alone is worth it. I junked my 19 in favor of a 40 a few years ago. Mine is aluminum but I believe there is a steel HP in that capacity as well.
 
al30 would be better for a variety of reasons:
takes a standard stage kit and is easy to sling
removable in case of entanglement
easy to donate gas to someone on the 40" hose
easy to check pressure on a 6" spg hose
30% more gas
convertible to an o2 deco bottle in the future

Not a fan of upside down pony bottles hard mounted to your main tank
 
al30 would be better for a variety of reasons:
takes a standard stage kit and is easy to sling - Would prefer to backmount and al30 is significantly larger than what I'm looking for. The advantage is it's actually shorter than al19, but wider in diameter.
removable in case of entanglement - I'm diving with multiple cutting tools, so if my backmount pony gets hung, stuff gets cut, if I can't cut it with my rig on, the rig comes off and I cut myself free
easy to donate gas to someone on the 40" hose - not necessary, I'm diving alone. If I were diving with someone, I would reconsider my rig.
easy to check pressure on a 6" spg hose - no need for a 6" spg hose, I know how much gas is in the pony bottle. I've either used it or I haven't.
30% more gas - In my rec dives, 19 or 23 is plenty of redundant gas for my purposes.
convertible to an o2 deco bottle in the future - No need for conversion for me. Just need a redundant air source.

Not a fan of upside down pony bottles hard mounted to your main tank - Why not? It puts the hose in prime position, makes the valve easily accessible and is protected because it's shorter than the main tank. Curious why you think this...
 
You have all the answers already with <50 dives so best of luck to you.

So have you been diving with either the steel 23 or aluminum 19 backmounted? Which do you think is better?
 
You have all the answers already with <50 dives so best of luck to you.
This is a really obnoxious answer to someone asking for advice and looking to discuss a new setup. Their response to you wasn’t rude, I don’t know why you feel the need to respond so harshly.

He’s looking to improve his setup to increase safety, are you of the opinion there is only one specific way to do this, and anyone who does anything else Is Going To Die?
 
This is a really obnoxious answer to someone asking for advice and looking to discuss a new setup. Their response to you wasn’t rude, I don’t know why you feel the need to respond so harshly.

He’s looking to improve his setup to increase safety, are you of the opinion there is only one specific way to do this, and anyone who does anything else Is Going To Die?

People have actually died with backmounted ponies. They apparently thought they were on their main tank, but were on pony and drowned when they ran out of air in pony tank. Pony reg was apparently on necklace. Slung pony with second stage that is bungeed to the pony means there is a lot less confusion between back gas and pony.
 
People have actually died with backmounted ponies. They apparently thought they were on their main tank, but were on pony and drowned when they ran out of air in pony tank. Pony reg was apparently on necklace. Slung pony with second stage that is bungeed to the pony means there is a lot less confusion between back gas and pony.

This seems unbelievable really. Whether the tank is slung or mounted is irrelevant. There are two regulators and two air sources. If one doesn't work, you use the other.

You have a main tank and regulator, you have a pony bottle and regulator. You put the main in your mouth and the pony is there for emergency.

If someone drowns because they drained their pony bottle, then they should have been prepared to switch over to their main tank, which would have been on from the start. If you are out of air, you switch tanks. It's why you have two tanks. No need to drown at all.

I'm simply asking for advice on which tank to use. If you haven't used either, just keep reading and don't respond. If you have experience with either or both, please let me know what you think of their performance.
 
This seems unbelievable really. Whether the tank is slung or mounted is irrelevant. There are two regulators and two air sources. If one doesn't work, you use the other.

You have a main tank and regulator, you have a pony bottle and regulator. You put the main in your mouth and the pony is there for emergency.

If someone drowns because they drained their pony bottle, then they should have been prepared to switch over to their main tank, which would have been on from the start. If you are out of air, you switch tanks. It's why you have two tanks. No need to drown at all.

I'm simply asking for advice on which tank to use. If you haven't used either, just keep reading and don't respond. If you have experience with either or both, please let me know what you think of their performance.

I actually have dove with a 19. It sucked. I like a 40 much better. I sold the 19 to a buddy whose jacket BC is incapable of handling anything bigger than a 19, as it doesn’t have D rings in the proper places.
 
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