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View Full Version : When would you choose HP over LP



shockere85
01-21-2009, 14:21
I am actually wondering when would you use each, and if you are answering what do you prefer for cold water diving.

fisheater
01-21-2009, 14:48
I prefer my HP120s, as they give me more air than an LP version of similar size.

DMWiz
01-21-2009, 15:00
Some people prefer LP tanks because they are almost always guaranteed a full fill (or overfill) while others feel that if the compressor cannot pump over 3000 psi the HP tanks are not getting fully filled. (I have never had that issue) I guess some older compressors or boat compressors have this problem.

I personally like HP tanks not because of the fill pressure difference, but because of buoyancy characteristics and size of the tanks I use.

Rainer
01-21-2009, 15:09
Let's break this down.

HP Pros
-Holds more gas than an LP in an equivalently sized cylinder IF both are filled to rated capacity (for similar capacity, this means a smaller HP cylinder).
-Can use to transfill to an LP cylinder (especially useful with large capacity HPs).
-A high capacity HP is still a lot of gas even if under-filled (e.g. HP100 at 3000 still beats an AL80).

LP Pros
-Easier to obtain a full fill (many compressors cannot go to 3500psi).
-Easier to do PP blending (matters if you plan to do your own mixing).
-Can use to transfill into from HP cylinder.
-Cheaper than HPs (used to be significant, now less so).
-If shop is willing to overfill, then you just bought HP at LP prices.


I have a mix of both for cold water diving (LP85s, HP100s, HP130s, plus plenty of ALs). The choice is dependent on what matters to you (cost, size, importance of mixing at home, etc) and what your local filling situation is like (availability of over-fills, type of blending, etc).

CompuDude
01-21-2009, 15:34
Rainer pretty much hit it. I prefer HP tanks, because many places (around here) will not knowingly overfill an LP tank. I'd rather they at least attempt to hit the 3442 (or whatever) limit than stop at 2400/2640. I also really dislike the Plus rating system... every 5 years, when you hydro your tank, it must be done by a facility that is (a) capable and (b) willing to do a proper certification to confirm the Plus rating of an LP tank. Otherwise the LP85 you just purchased (which holds 85cf of gas when the Plus rating is current and can thus be filled to 2640 instead of the regular 2400 psi level) is now technically only allowed to be filled to 2400 psi, which leaves you with 77cf of allowable capacity. That's not what I buy steel tanks for. I'd rather have the HP100, where I may or may not get the full 100cf of gas, but at least there's no chance someone will stick me with a 2400psi fill because I couldn't find a hydro facility that Plus certifies my tank. (They're not easy to come by in all areas.)

MSilvia
01-21-2009, 15:44
Good answers. I use both for cold water. Currently HP100 doubles with LP72 singles, but I'm about to switch that to LP72 doubles and HP100 singles.

skdvr
01-21-2009, 18:22
I only have HP's... The shop that I mainly go to would overfill LP if you ask for it, so I would not object to LP tanks. If buy a LP tank with the idea that you are going to get the rated fill out of it, and then if you can get overfills then BONUS. Otherwise I say buy HP and if you want you can underfill them if you want.

Just for instance I have one HP 130, the LP equilivant is the LP 108. They are roughly the same size. You can underfill the 130 anytime that you like to get around 100cf. But if you can get overfills the LP 108 actually gives you a bit more gas.

LP108 @ 3500psi = 142cf of gas
HP130 @3500psi = 132cf of gas

If I found a good deal on LP tanks I would not pass them up, but me personally if I am buying new I am getting HP, just because around here it is easier to get the good fill without having to hope someone will overfill for me...

Phil

in_cavediver
01-21-2009, 19:30
I have entirely LP steels. Didn't really plan it that way and I did have an HP 120 at one point. Its just what was cost effective and works.

My 104's came before the advent of the HP130. Not really a choice there
My 85's (all 4) came at prices as a pair that was on par for a single HP 100
My 45's were deliberate - for transfilling O2. Again, they came cheap - 400 for a pair with manifold and bands.
My 72's were free. Can't argue with that.

As for overfills - generally, my tanks get DOT fills for local dives and cave fills for cave dives (or deep dives). I've never had a problem with getting fills I wanted. Though one day I was at vortex and they asked how much I wanted in the 104s and I said 3600 - they laughed and said they fill it so long as I stood by it. It made 3400 when he shut it down. (equalized the bank on it)

digital_steve
01-21-2009, 19:42
I got 300bar tanks (i suppose what you guys call HP) for my twin 7's setup because of their buoyancy characteristics. It means less weight on the belt for me and less faffing about with pockets/weightbelt at a divesite

Rainer
01-21-2009, 19:47
The buoyancy characteristics for the HP and LP steel cylinders (at least most of the newer ones) are the SAME.

DMWiz
01-21-2009, 20:43
The buoyancy characteristics for the HP and LP steel cylinders (at least most of the newer ones) are the SAME.

For me they are not quite the same check this chart:

Faber Cylinder Specifications (http://www.bluesteelllc.com/products.htm)

DMWiz
01-21-2009, 20:50
Here's an even better chart:

Scuba Cylinder Specs (http://www.tdl.divebiz.net/pub/tanks.html)

Rainer
01-21-2009, 21:40
Well, Jesus, man, who dives Fabers???

:)

shockere85
01-21-2009, 21:57
What are some of the more perferred tanks to buy if you are going with an HP then

Rainer
01-21-2009, 22:12
What are some of the more perferred tanks to buy if you are going with an HP then

You seem to be attacking this all wrong.

What are YOUR needs?
-Based on SCR
-Based on dive sites (depth, square vs. multi-level)
-Based on future plans
-Based on shop fill ability
-Based on your size
-Etc

What does it matter what others dive?

DMWiz
01-21-2009, 22:24
Well, Jesus, man, who dives Fabers???

:)


I like them:smiley2:... I also like the X8-130s which are not the same as the lp 108s

digital_steve
01-21-2009, 23:07
must be talking about different things then
300bar tanks (faber) are more negative than their 232 bar cousins

Rainer
01-21-2009, 23:17
PSTs and Worthingtons (what real men dive) are about equivalent for LP and HP in terms of buoyancy. Almost all are around -2 empty.

in_cavediver
01-22-2009, 05:25
PSTs and Worthingtons (what real men dive) are about equivalent for LP and HP in terms of buoyancy. Almost all are around -2 empty.

I guess those fabers I bought for Sidemount are 'boys' tanks then eh.....

Tanks are tanks. Each offers advantages and disadvantages based on its specs. Faber, PST and worthington are all good brands.

DMWiz
01-22-2009, 05:28
PSTs and Worthingtons (what real men dive) are about equivalent for LP and HP in terms of buoyancy. Almost all are around -2 empty.

What is it with you people:smiley36: I've been called "not a diver", "a noob" and now "not a real man" all because of my gear choices!:smilie39:

BTW X8's are Worthingtons :smiley20: The 108 is neutral while the 130 is -2.

skdvr
01-22-2009, 07:19
PSTs and Worthingtons (what real men dive) are about equivalent for LP and HP in terms of buoyancy. Almost all are around -2 empty.

What is it with you people:smiley36: I've been called "not a diver", "a noob" and now "not a real man" all because of my gear choices!:smilie39:

BTW X8's are Worthingtons :smiley20: The 108 is neutral while the 130 is -2.

According to XS Scubas chart on Worthington Tanks they are both Neg

http://i284.photobucket.com/albums/ll34/pebalsamo/LP.jpg

http://i284.photobucket.com/albums/ll34/pebalsamo/HP.jpg

Phil

DMWiz
01-22-2009, 08:52
According to XS Scubas chart on Worthington Tanks they are both Neg

Phil

Interesting, I passed up on a pair of 108 based on their slight differences (height & buoyancy). I wonder if they have changed over time?

Rainer
01-22-2009, 09:55
A joke people. Get over yourselves.

And diving in the colder ocean, -2 is a better than neutral. Just weight off the belt.

:)

MSilvia
01-22-2009, 11:19
PSTs and Worthingtons (what real men dive) are about equivalent for LP and HP in terms of buoyancy.
Pish. Real men dive Asahi HP100s (-7 empty). Doubled, lesser men can't even lift them.

Sorry girls, I'm taken. ;)

Rainer
01-22-2009, 11:24
I guess that means it's about time I double my two up, huh?

;)

P.S.
Didn't you just say you're breaking yours down?!

in_cavediver
01-22-2009, 11:28
Real men.... REAL men dive DOUBLE heiser 190's
Sure, they look like water heaters but gas is gas.

(fill pressure 4400psi, empty - 46.8lbs, full -62.3lbs EACH. They give the 100lb wings a reason to exist)

MSilvia
01-22-2009, 11:28
Didn't you just say you're breaking yours down?!
Yes, but only because I think they'd serve me better as singles. I'm still going to dive them.

Rainer
01-22-2009, 11:33
Didn't you just say you're breaking yours down?!
Yes, but only because I think they'd serve me better as singles. I'm still going to dive them.

Are you finding yourself limited by the 72s for local shore dives? It's funny being out here in CA now, where at least two sites get to >100' (fast) from shore. I always found my HP100s overkill for Cape Ann, but just recently went to HP130s for shore dives here, as even the 100s weren't cutting it. Nothing like 90+ minute dives at Back Beach or OGB, coming out with 1000+ psi...

Those Asahi/Genesis cylinders are great for singles; I just know I wouldn't want them doubled (they're awful negative!).

shockere85
01-22-2009, 17:15
What are some of the more perferred tanks to buy if you are going with an HP then

You seem to be attacking this all wrong.

What are YOUR needs?
-Based on SCR
-Based on dive sites (depth, square vs. multi-level)
-Based on future plans
-Based on shop fill ability
-Based on your size
-Etc

What does it matter what others dive?

Im not really sure what SCR is but im a beginner driver who is going to be diving Lake erie most of the time. I am very in the wreck diving and in lake erie the range is avg 63ft to as deep as 213ft. I do plan on becoming a tech diver so i've been looking at steel HP100s. My dive shop recommends steel. I am 240 lbs but I use to be a avid bodybuilder so I am trying to get down to 220, at 5'11. i would enjoy staying under as long as I can. I have a nitrox class on febuary so I will be Nitrox certified

digital_steve
01-22-2009, 18:26
I guess those fabers I bought for Sidemount are 'boys' tanks then eh.....

Tanks are tanks. Each offers advantages and disadvantages based on its specs. Faber, PST and worthington are all good brands.
Which fabers are you sidemounting?

Rainer
01-22-2009, 19:40
Start by forgetting about tech diving (for the next few years) and just enjoy your recreational diving (while working on trim, buoyancy, etc).

For dives down to 100' (a reasonable cold water depth limit for new divers), a HP100 would serve you well. If you can swing two, get them matched for height, so you'd always have the ability to double them up in the future.




What are some of the more perferred tanks to buy if you are going with an HP then

You seem to be attacking this all wrong.

What are YOUR needs?
-Based on SCR
-Based on dive sites (depth, square vs. multi-level)
-Based on future plans
-Based on shop fill ability
-Based on your size
-Etc

What does it matter what others dive?

Im not really sure what SCR is but im a beginner driver who is going to be diving Lake erie most of the time. I am very in the wreck diving and in lake erie the range is avg 63ft to as deep as 213ft. I do plan on becoming a tech diver so i've been looking at steel HP100s. My dive shop recommends steel. I am 240 lbs but I use to be a avid bodybuilder so I am trying to get down to 220, at 5'11. i would enjoy staying under as long as I can. I have a nitrox class on febuary so I will be Nitrox certified

in_cavediver
01-22-2009, 20:03
I guess those fabers I bought for Sidemount are 'boys' tanks then eh.....

Tanks are tanks. Each offers advantages and disadvantages based on its specs. Faber, PST and worthington are all good brands.
Which fabers are you sidemounting?

LP 85's - filled like HP tanks though:smiley2:

skdvr
01-23-2009, 06:44
Start by forgetting about tech diving (for the next few years) and just enjoy your recreational diving (while working on trim, buoyancy, etc).

For dives down to 100' (a reasonable cold water depth limit for new divers), a HP100 would serve you well. If you can swing two, get them matched for height, so you'd always have the ability to double them up in the future.




What are some of the more perferred tanks to buy if you are going with an HP then

You seem to be attacking this all wrong.

What are YOUR needs?
-Based on SCR
-Based on dive sites (depth, square vs. multi-level)
-Based on future plans
-Based on shop fill ability
-Based on your size
-Etc

What does it matter what others dive?

Im not really sure what SCR is but im a beginner driver who is going to be diving Lake erie most of the time. I am very in the wreck diving and in lake erie the range is avg 63ft to as deep as 213ft. I do plan on becoming a tech diver so i've been looking at steel HP100s. My dive shop recommends steel. I am 240 lbs but I use to be a avid bodybuilder so I am trying to get down to 220, at 5'11. i would enjoy staying under as long as I can. I have a nitrox class on febuary so I will be Nitrox certified

I agree, if you can buy 2 of the 100's now, do it. It can be tough to match up two tanks down the road to double them up when you are into Tec diving. I agree with Rainer to just work on Buoyancy control, Trim, confidence in the water before starting down the Tec path.

Phil