Filling High Pressure Tanks vs Low Pressure Tanks

[Dr. Lecter]

But I think anything over 3k is actually harder on your regulators... regardless of the tank rating...

I don't know what regs you dive, but mine are rated for use at pressures above 4000psi; the 3600 or 3700 my HP 100s and 130s max out at are not going to hurt them. Though I'll agree that just about anything's better than an AL80

 

[chrpai]

Though I'll agree that just about anything's better than an AL80

When Lake Travis warms up (like now) I can actually dive to 40' in swim trunks. When I do that, an AL plate and AL80 is all I need for a good time. No additional weight. And if that's not enough gas... you should read about the time I picked them up from the shop with 3800psi in them. Oops...

 

[pocky21]

Around here Windy Point usually doesn't have that much pressure and I've been told that the M/V Fling (Flower Gardens) doesn't either. There was a big fuss from some divers complaining that the boat policy charged a surcharge for 100+ tanks but then didn't actually fill 100cf in the tanks.

I stand corrected. I can understand to a certain degree on a boat, but for a retail center I would associate that lack of 500psi with "we don't want to stress the compressor" or "we don't want to invest in a system for that" or any "we're being cheap" kind of arguments - thus I would be lead to question other corners they may have cut.

 

[spectrum]

Sandy,

I guess the crux of this revolves around what you called the low pressure hose. If it got you to 3442 is was apparently of a high enough pressure for the task. Any air from a fill whip should be suitable though some may be oxygen clean as well.

If you saw the whip(s) marked as low pressure and other(s) high the shop may be equipped to fill some very high pressure (4500-5000 PSI) specialty cylinders like scba units. Part of the bank may be dedicated to topping those off and they configured it with dedicated whips.

Can you further describe what was marked and exactly how?

Pete

 

[Superlyte27]

They weigh less, trim out better, and are perfectly fine in terms of volume if you have a proper fill station.

Weigh less than what? It depends on which HP100's and which LP85's. Trim out better? For who? not all tanks are created equal for everyone. For example, lots of people can trim just fine in LP95's, but you couldn't get me in trim with them without adding weight (which is stupid imo).

There is no one single perfect tank. Personally, I think LP85's are better in every single way than HP100's including cost. But I fill in cave country. If I lived in Canada, obviously the HP100 would be a better tanks, all other things being equal.

---------- Post added August 27th, 2013 at 11:38 PM ----------

Have you ever tried to lift a LP120?

My HP120's are a load, but manageable. Not so with the LP variant. . .

But an LP85 filled to 3600psi holds virtually the same thing (116cu') as your HP120 and weighs significantly less.

---------- Post added August 27th, 2013 at 11:41 PM ----------

HEY... I didn't say that...

I do know that I really like my LP85's over Al 80's.... And though I know these are "LP" I don't mind the shop filling them to 3k... though I tend to get a little upset if they give me a real "CAVE FILL" the additional 600psi really isn't that big of a deal in the grand scheme of things... But I think anything over 3k is actually harder on your regulators... regardless of the tank rating...

---------- Post added August 27th, 2013 at 09:39 PM ----------


That totally goes against everything I've been told... of course AL 80's only being 75 or 76 CuFt messes me up too... I thought the Steel tanks were truer to their actual size...

Imbodie... an AL80 is 77.4cu'. Unless it's a goofy neutral at 80 or 3300psi 80. But run of the mill AL80 should be 77.4cu'.
Also, your faber tanks are rated at 85cu' at 2640. If they didn't have the + rating, they'd be 2400psi tanks.

 

[lpurcell]

Back to the subject of fills....... I still have some steel 72s (2250 psi). I can't count the number of times I've gotten them back at 3000 psi or better simply because the kids at the fill station simply didn't check (these tanks are older than most of the dive shop staff). Now I make it a point to tell them they are 2250.

 

[Superlyte27]

Those tanks scare me.

 

[Dr. Lecter]

Weigh less than what? It depends on which HP100's and which LP85's. Trim out better? For who? not all tanks are created equal for everyone. For example, lots of people can trim just fine in LP95's, but you couldn't get me in trim with them without adding weight (which is stupid imo).

There is no one single perfect tank. Personally, I think LP85's are better in every single way than HP100's including cost. But I fill in cave country. If I lived in Canada, obviously the HP100 would be a better tanks, all other things being equal.

Did you read the post to which you were replying? I could care less what works for you, though I don't doubt that it does. I was simply replying to a 'gosh, what could ever possibly justify getting an HP tank over an LP tank?!111oneoneeleven' post.

But an LP85 filled to 3600psi holds virtually the same thing (116cu') as your HP120 and weighs significantly less.

As you say, you live in cave country. Lots and lots of people don't.