HP vs. LP / High Pressure versus Low Pressure steel tanks

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pescador775,

Thank you very much for all the information.

Like I said, I'm a pretty new diver,but, I've already wasted a lot of cash on gear that I wish I didn't now own.

Here's what I got:

Mares low volume mask/quattro fins
Apex 200 primary reg (7'hose)
Sequest Shado integrated air source
Seaquest Pro weight integrated BCD
Suunto FAVOR computer on console w/ gauges(can't have stuff on arms when reaching into lobster holes)
Diving concepts dry gloves/set of neoprene gloves
120hps tank
80al tank
Manta Wreck bag
Manta Senior reel
EMS shears and knife on chest, blunt pry knife on leg
Whites Dry suit
Seaquest Cold water 7mm jumpsuit

I do a lot of shore dving in remote places, often a night, I also do a lot of diving off a small boat. While I enjoy sport diving for lobster and scallops and doing shallow wrecks, I aspire to learn to dive deeper wrecks (the deepest I have done is a tanker in 100" w/instrutor) - bottom temp 45deg (it's chilly here and low viv is considered the norm).
One day I hope to the Doria and several other deep wrecks in the area. I'm hoping to do the U-853 this summer.
I dive with NITROX when I can, but, I have no experince with any other gas.

What strikes you as the first piece of gear I should add/replace?
Thanks again for the advice.
 
Originally posted by pescador775
...pompous arse as the DIR gurus.
...disingenuous...
...high priests...
..."little red books"...
...Scientologists...
...Muslim "activists".
...it would be heresy.
...relentless proselytising.
Then, a couple replies later...
Originally posted by pescador775
...we shouldn't be making any ad hominem arguments...
That would be funny if it wasn't so pitiful.

DIR can't change? Big profits?

Those two statements alone shows you don't know JS about DIR.

Roak
 
The PST HP sound great!...but I have heard some say that the increased pressure is tough on regs...that it might increase wear to seat and other components. Is this true? Do HP steel cylinders have any negative affect on equipment?

This concern has me leanig towards PST's LP Pro series as opposed to their HP Sport.

Thank you kindly!
Lisa:wink:
 
Lisa,
We had this discussion a while back. Sorry I haven't figured out how to find it! HP seats in balanced regs are not affected by tank pressure. In fact, that could be the definition of a balanced reg. The only closing force on the seat is intermediate pressure, which should remain constant. Regs are designed to handle the pressure in any case. Use the HP if you like it!

Neil
 
Originally posted by MASS-Diver
pescador775,

Thank you very much for all the information.

Like I said, I'm a pretty new diver,
:rolleyes:
whooooeee....
Shoot MASS....
There is a big difference between good information & bad information....
Pesky *can't go into the whys and wherefores* but at least he warns you to think about it....
And I would advise you to think about it too....
Learning stuff off of a open bulletin board is fraught with danger for the undiscerning....
You already say you bought some wrong stuff....
Don't let it bother you too much....
That is part of your tuition and then there is ebay....
But you don't want to go making mistakes learning the wrong stuff....
 
Originally posted by Lisa M
The PST HP sound great!...but I have heard some say that the increased pressure is tough on regs...that it might increase wear to seat and other components. Is this true? Do HP steel cylinders have any negative affect on equipment?

This concern has me leanig towards PST's LP Pro series as opposed to their HP Sport.

Thank you kindly!
Lisa:wink:

No, HP steel cylinders have no negative impact on your equipment, there are a lot of other reasons why you want to stay away from HP tanks. If anything the HP steel tank itself is stressed more than a LP tank. PLus the fact that LP tanks are easier to fill and you get relatively more air if you overfill them as opposed to overfilling a HP tank. I know we are not supposed to overfill but i mention it anyway because it is a common practice.
 
These terms are generally applied to steel tanks in the US.

LP = low pressure, typically either 2400 or 2640 psi (although tanks with even lower pressures down to 1800 psi are about)

HP = high pressure, typically over 3000 psi, with 3500 psi being common

An 80cf LP tank holds the same amount of gas as an 80cf HP tank (which, funnily enough, happens to be 80cf).

Comparatively, aluminum tanks are generally 3000 psi, 3180 psi or 3300 psi, and are not referred to as LP or HP.
 
In addition,

HP tanks - popular with some due to their smaller size and lighter weight relative to their capacity

LP tanks - populare with some due to their negative bouyancy characteristics which can allow certain drysuit divers to remove all or part of their weight from their weight belt and rely on the negative bouyancy characteristics instead

Dave D
 
https://www.shearwater.com/products/peregrine/

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