HP vs LP

[jfg]

I had a diving friend, who has always used aluminum tanks, ask me the question,"why use high pressure tanks instead of low pressure tanks"?

Well, being a novice, I really couldn't give him an inteligent and acccurate answer, so how about some users of both HP and LP answer this for me. I'll print this off and let him see your responses.

By the way, he wasen't being a smart azz, he really didn't understand why anyone would opt for those high pressures.

If there is a thread on this, please lead me to it instead of trying to lick this calf all over again,
thanks,

[bgbill]

Try the search and you will find a bunch of info.

I dive HP 120's, LP 120's, LP 121's and LP 125's and prefer the LP, because you can always get a full fill and when they are over pressurized hold a lot more gas.

And if you ever get into mixed gas diving the LP's are easier to deal with.

Lp's are less prone to internal corrosion (rust) than HP's.

Where I notice the weight difference is loading and unloading the boat, the Lp's are heavier, in the water they feel basically the same.

I dive DIN regs, but my LP's have convertable valves, and it makes getting them filled easier.

With doubles I like the HP 120's because they are easier to deal with on the boat, but I also have 3 sets of LP doubes.

[WreckDiver]

LP tanks are rated with the original + rating, a steel LP 80 is only an 80 for the first 5years unless you are lucky enough to find someone willing to risk the liability. other wise your stuck with an exspensive lp72. I personaly like the PST e series no problems getting them filled to spec.

[dagodiver]

Originally posted by Bugged
LP tanks are rated with the original + rating, a steel LP 80 is only an 80 for the first 5years unless you are lucky enough to find someone willing to risk the liability. other wise your stuck with an exspensive lp72. I personaly like the PST e series no problems getting them filled to spec.

Same same,
E-series singles and doubles...

[f94gator]

Personally, 2 main reasons I like hp's

1) Aren't the size of water heaters and fit in any tank rank
2) A big LP can hold more air, sure - but diving hp 120's at 80+ ft, I find myself running into deco long before running out of air becomes an issue. Don't need the extra air.

[zds3488]

I have 2 HP and 2 LP 120s. LP are heavier, but hold WAAAAYYYY more gas if filled by a spearfishing friendly dive shop!

[kitefisherman]

Zack - don't tell them that! Leave more fish for us. BTW, the LP is heavier BECAUSE it has more air in it.

[zds3488]

Empty, the LP 121 is the same weight as a full HP 120...

[kitefisherman]

Originally posted by zds3488
Empty, the LP 121 is the same weight as a full HP 120...

That's comparing apples to oranges. A HP 120 and a LP98 both filled to 3800 PSI both weigh the same, yet the LP holds more air. Comparing a HP 120 to a LP 121 doesn't ake any sense because at 3800 PSI the LP holds about 50% more air than the HP.

[Charlestondivin]

LP's Rock! Especially for an Air-Hog like me.

[100days-a-year]

LPs cheaper,LPs more gas at same 3000 to 3500 that most shops fill all tanks to.
HPs fit better in tank racks,HPs good for people anal about overfills,HP can be lighter in certain cases.
6 of 1 ,half dozen of another, just don't overfill AL tanks.

[jfg]

Sounds like LP's are the favorite. Yeah, my friends thoughts were that LP's would just be easier to fill to spec, especially on some of the older compressors struggling on that last 20% of fill.
Thanks for the input guys, good stuff.

[dagodiver]

Originally posted by 100days-a-year
LPs cheaper,LPs more gas at same 3000 to 3500 that most shops fill all tanks to.
HPs fit better in tank racks,HPs good for people anal about overfills,HP can be lighter in certain cases.
6 of 1 ,half dozen of another, just don't overfill AL tanks.

Same Same LP's are great
plus better for 3mix in cascade system, He not cheap..
Dago