Why choose LP tanks over HP Steel tanks?

[JackD342]

I had no issue th

Possible and valid theories, but until the quarry which possibly might not fill LP Tanks is named and we can ask directly, ...just theories. With my very, very limited Quarry exposure (and having just 1 LP tank for 1 year so far, I did not run into an LP refill issue yet.

Well, @Marie13 makes it obvious in her posts where her LDS is, so the most likely quarries are Haigh and Pearl Lake. I'll probably be at Haigh next weekend (season close) and will ask if I remember.

 

[Schwob]

Well, @Marie13 makes it obvious in her posts where her LDS is, so the most likely quarries are Haigh and Pearl Lake. I'll probably be at Haigh next weekend (season close) and will ask if I remember.

I hope to be there Sunday next week... and while I got most of my fills at that same LDS (had a card) and not at the quarry this season, I at least thought they had filled my LP tank once, but am not sure, hence I wait saying until I am... Have however not been at Pearl with an LP... but at Mermet it was fine for sure last Nov.

 

[boulderjohn]

Your ability to get fills at your hoped-for pressure depends not only on the region, but also on the individual shop.

In one location I have used a lot, I used to get my recreational fills at the same place I did my diving. I would drop off my LP 85s the day before and pick them up just before the dive. The problem was they would rarely be filled to the service pressure (2640 with the +). They were usually filled at around 2400. If I asked for a topoff, I could usually get a little more. Not much. One day when the manager was doing that topping off, he said my complaining about it was just "splitting hairs." He said filling LP tanks to their rated pressure (or above) was too dangerous, and he could not ask his employees to do that.

At that same place, though, it was different for other tanks. When friends of mine dived with the same operation, they rented AL 80s, and those were always filled to about 3300. Thus, they had more gas in their AL80s each day than I had in my LP 85s.

One day there was a sudden change in plans for the dive site, and my nitrox fill had an unsuitable MOD. They quickly gave me an HP (3442 PSI) they had filled for someone else who could not make the dive. It was filled to 3700 PSI.

So when I realized the shop regularly overfilled anything except LP tanks, I took mine to a different LDS a couple miles away for fils. Their standar policy was to fill LP tanks like mine to 3,000, but that rarely happened. It was usually more like 3300 or 3400.

Conclusion: There are no reliable ways to predict how your tanks are going to be filled at locations you don't know.

 

[scubafanatic]

boulderjohn makes a good point, dive shops are all over the map with respect to their fill policies, and sometimes the shop remains the same but under goes an ownership change and then your grand tank buying strategy goes up in smoke! I remember one shop (went out of business about 2006 or so) where asking for a slight overfill would lead to a lawyerly lecture and a stern refusal, they could be so anal about things, it was so tiresome and they were scared of their own shadow, mindlessly by-the-book!

 

[Schwob]

@boulderjohn & @scubafanatic
yes.
But part of the discussion went in the direction of not being able to get any fill at all with an LP tank (good, better or just near 2400 PSI). A statment made by @Marie13, until clarified could indeed be interpreted as if some shops at quarries near enough to Chicagoland would not fill LP tanks at all. That has been questioned by various posters and is awaiting clarification...

 

[MichaelMc]

Interesting about the fills. I have local friends who tell me they have trouble getting LP fills. HP fills are not a problem .

@boulderjohn & @scubafanatic
yes.
But part of the discussion went in the direction of not being able to get any fill at all with an LP tank (good, better or just near 2400 PSI). A statment made by @Marie13, until clarified could indeed be interpreted as if some shops at quarries near enough to Chicagoland would not fill LP tanks at all. That has been questioned by various posters and is awaiting clarification...

I would not interpret 'trouble getting LP fills' as them not filling the tank at all. Any more than I would interpret 'trouble getting HP fills' that way. But rather as trouble getting it filled it to either spec when cooled or generously, depending. I understand not filling generously, but if you then over fill other tanks that are less suited to it, like AL, I understand less. I really do not understand under filling below spec because it is LP. Where they wronged by an LP tank once? Or not want the divers that might use them?

For Nitrox there may be some issue that people then log the fill, creating a record the shop might be less happy about having.

 

[JackD342]

All my LP tanks are more negatively buoyant than my HP. Weight off the belt.

As availability of HP fills, not usually an issue to me, but on boats with quick fills mine is always good and HP tanks are short fills.

I like steel and usually buy when I can find a good deal regardless of pressure. I do like to find Faber MP tanks, but that's just me.


Bob

Interesting - Faber's specs appear to show their LP cylinders are slightly more positive when empty, compared to their comparable volume HP..
Blue Steel Scuba - Cylinder Specs
Maybe yours are a different make?
Main take away: if a few pounds of buoyancy are a primary shopping consideration, get into the specs on specific cylinders, rather than generalize aluminum v steel and LP v HP.

 

[Bob DBF]

Maybe yours are a different make?

Older tanks, I haven't bought a new tank since some Al 80s over four decades ago. Some are LP 2400 #, some are also refered to as MP both 3000 and 3180# service pressures.

From the specs on the new Faber LP tanks, I won't be buying any.


Bob

 

[mnscuber]

You know, I hesitated before typing out the wear and tear comment, but decided it should be out there. I wish I had a solid source for attribution I could point you to, but I don't. I have heard/read it several times over the years, but I don't remember exactly where. It came up again sometime in the last year that I remember at the time thinking to myself after reading that it was reliable confirmation of previously acquired info. Again, wish I could remember where. I'll be interested to see other/future comments at large.

Thanks for the conversation. I've been noodling on this as well. Here's a source:
How to Select a SCUBA Tank | Dive Gear Express®

 

[runsongas]

cave fills or fill station problems where you don't get a good high pressure fill. like if say the FNG at your LDS decided to fill your hp100s and lp80s all to 3000 psi last week because he wasn't trained to deal with anything other than an al80 or just DGAF.