How much air does an LP85 hold at 2400 PSI?

[lexvil]

I do boat dives, no shore diving and would like to know if for deep diving if i am better off with LP or HP tanks. Thanks.

You’re better off with full tanks…

Deep is one thing, how long is another.

 

[TravelGas]

Unless the cost difference is dramatic, the hp version is always the better choice.

Thanks Tracy.

As for the double AL80's, the boats I am looking to go out on, won't even allow me to dive those wrecks with less than double 100's. My LDS fills HP tanks no issue.

 

[TravelGas]

You’re better off with full tanks…

Deep is one thing, how long is another.

Lexvil, yes I always want full tanks no matter how much pressure that is.
Deep is deep and I plan on staying plenty long, Need large tanks and plenty of them.

 

[Bob DBF]

I do boat dives, no shore diving and would like to know if for deep diving if i am better off with LP or HP tanks. Thanks.

Out on the west coast many boats fill onboard, but they may have a 3k compressor, or with a HP compressor they may not have time between dives to give a good fill. I found a good deal on a LP 95, which is not my favorite tank, that I take on those boat dives so I always get a good fill.

If you have to bring on-board filled tanks to dive, then tank pressure no issue.

 

[inquis]

Need large tanks and plenty of them.

Maybe, maybe not. For most of the deep dives I've been looking at, the limiting factor is the amount of deco gas, not the amount of back gas. This is especially true when trying to run 2 dives without refilling deco cylinders. I use LP85s (with about 95-100 cf in them), and if I needed more bottom gas, I would just add a stage.

My point being, simply getting the biggest tanks you can may not be the best choice.

 

[Tracy]

You’re better off with full tanks…

Deep is one thing, how long is another.

This isn't really true, as it has no bearing on the gas you are carrying.

If you have an hp100 filled to 3200 psi or an lp85 filled to 3200 psi.
The hp100 isn't full, the lp85 is overfilled and yet you still have the same volume of gas for the dive.
But if the shop fills it to 3500, you have more, most shops won't fill your lp85 to 3500.

Which comes back to, the high pressure version is always the better choice unless it is considerably more expensive.

 

[lexvil]

This isn't really true, as it has no bearing on the gas you are carrying.

If you have an hp100 filled to 3200 psi or an lp85 filled to 3200 psi.
The hp100 isn't full, the lp85 is overfilled and yet you still have the same volume of gas for the dive.
But if the shop fills it to 3500, you have more, most shops won't fill your lp85 to 3500.

Which comes back to, the high pressure version is always the better choice unless it is considerably more expensive.

so lp 85 and an hp 100 have the same volume until you get to 3500 and then the 85 has more? Point is you get lousy fills on a boat which is unlikely to fill anything to 3500.
is a LP 85 the exact tank as the HP100? The LP 95 is a great boat tank, for volume

 

[Tracy]

so lp 85 and an hp 100 have the same volume until you get to 3500 and then the 85 has more? Point is you get lousy fills on a boat which is unlikely to fill anything to 3500.
is a LP 85 the exact tank as the HP100? The LP 95 is a great boat tank, for volume

They have the same volume, the pressure is irrelevant. They aren't completely identical, but close enough for their purpose. LP95 is a fine tank, but if you can find an hp117 for the same money, it makes more sense to buy it instead. Same tank volume means better fills when you can get them, same fills when you can't.

 

[Storker]

Can someone save me the reading of an 18 page thread and just tell a layman if I should be buying LP or HP, if I want as much air as possible in the tank for deep diving ? Thanks.

Buy a tank which has a rated capacity beyond your min gas requirements. Service pressure doesn't matter (except for your weighting), total capacity does matter.

EDIT: Provided you can get proper fills to your tank's service pressure. You'll still get short fills if the tank monkey just fills up and doesn't top up when the tank has cooled down.

 

[lexvil]

They have the same volume, the pressure is irrelevant. They aren't completely identical, but close enough for their purpose. LP95 is a fine tank, but if you can find an hp117 for the same money, it makes more sense to buy it instead. Same tank volume means better fills when you can get them, same fills when you can't.

I would like to see the cut apart side by side, I’ll give up an 85 to the test if you’ll give up a 100
I agree it’s better to buy an hp version when available.