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High PSI. Because you can still fill them to Low Pressure if you want and get the same amount of volume. A high psi 100 filled to 3442 psi will have 100 cu ft of gas....but, fill it to only 2640 like a Low pressure and you’ll have 80 cu ft.
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High pressure to be sure. I have used them for 10 years, and love the extra 500 psi that I get.
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From lars:
If I wanted 80cf, I would have purchased a cylinder that supplied 80cf, vs. under filling.
LARS, what’s the average filling on a 80. When I have mine filled I always fine it’s been filled to different levels by different shops. Should I be asking or requesting a speific fill or will the shops just do what they want to do?
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I could not have said it better then lars
I use LP 121 Steel tanks with a full service psi of 2400PSI but my tanks are also Plus tanks, I can over will then to 2640PSI then I have more than 121 cubic feet of air in one tank. One thing you’ll find a lot is a lot of dive shops like to bank there air & 99% of the time they can’t fill over 3000PSI so if you have a HI psi tank you not not get a full 121 cubic fill.
But it’s all in what your going to dive, like Lars said they are a little heaver then a HI psi tank. Then LP 95’s come in handy!
Hope that helps some
- Dale
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From
oceanfloor: LARS, what’s the average filling on a 80. When I have mine filled I always fine it’s been filled to different levels by different shops. Should I be asking or requesting a speific fill or will the shops just do what they want to do?
The Average fill on a aluminum 80 is 3000PSI But a lot of times when dive shops fill tanks they don’t take a lot of time filling them & the tanks will get warm then when they cool the PSI drops with the temp. On 80 cubic foot tanks you can tell a little more then you can with a 121 cubic foot. Guess because of the volume VS. a 80 cubic foot.
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Ok? That’s 2 for HP and 2 for LP!! What to do?? LOL!!
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Maureen,
What tanks have you dove so far and how did they feel? Larry made an excellent point that I never really ever thought about. One of my fellow divers have two sets of Double 80 LP’s made by Pressed Steel. He changed the burst disc and fills them to 3500psi. According to him and our head instructor, those specific tanks are no longer manufactured. I tried them out and they felt great, they’re even smaller than my Double AL80’s . And with an overfill to 3500psi, it’s like having Double 116’s. Bottom line is size and weight does matter when it comes to tanks and you need to feel comfortable with what’s on your back.
One other thing I wanted to point out (if you’re not already bogged down with enough to think about) is from the maintenance side of it. Steel tanks, regardless of high or low pressure need to be tumbled in addition to O2 cleaned especially if used for Enriched Nitrox or Trimix. Tumbling is definitely labor intense (if you’re doing it yourself) and if you’re paying a shop to do it, quite costly. My shop charges $95 per tank to tumble.
I have gradually shifted from diving Steel to Aluminum. Although steel is great in the water, on land they are a pain. From carrying to caring, it’s labor intense.
Ben
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I like AL tanks I have 2 al 80s I use, I dont think I would even think of steel if I were doing a lot of saltwater dives.
Steel is heavier so carrying your gear is going to be more of a chore.
Price for steel is going to be higher so that should be considered also.
one more thing I thought of, if you end up traveling and need to rent tanks more than likely it will be an AL tank. your weighting is going to be different from AL to steel.
So I guess my vote goes to aluminum tanks
I have always thought of HP steel as more commercial than rec diving but thats just my opinion.
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I have 2 al 80’s myself, bought em both the sametime used, passed hydros & vips, I myself use what I have and are happy with!
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From knightddiver:
I like AL tanks I have 2 al 80s I use, I dont think I would even think of steel if I were doing a lot of saltwater dives.
Steel is heavier so carrying your gear is going to be more of a chore.
I have friends that’s used the same steel tanks for years & salt water is all they dive. No rust! I have Worthington XS Scuba steels that cost about $450 per tank but I’ll never have to buy another set of tanks for a very long time. Steel is heavier so that means you don’t have to put on as much weight!
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I dive with 100s that are LPs. However I use a drysuit and am a bigger guy so less weight that has to go into my BC weight pocket. Don’t take this the wrong way but if you are a smaller build or don’t want to lug around a heavy tank go with HP. However HPs cost more, and not all filing stations can do the 3,000 plus PSI.
Also depends if you are looking at new or used. I have seen a lot of used LPs.
Hope this helps!
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I wont get into a argument at all because I dont own steel, But of the point of less weight to get you down I use 18 pds to get me under, is steel only that much heavier than aluminum? I do get the point of durability but again my uncle has over 18 years on his al 100 tank and a al 80 going on 15 passed hydro and vis no problem, but I concede that steel is going to be more durable.
To me I was under the impression that rust was a factor for steel and salt water would accelerate that so hey I could be wrong on that again I don’t own steel so.
My opinion is still for aluminum which would be lp but its just my opinion.
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I have 4 hp 80’s made by PST (no longer avail by that company) and they are great. They are smaller in dia, shorter and there is not that much wieght difference due to the smaller size.I just adjust my wieghts accordingly. Steels if taken care of will also last longer than al. Most of my dive have been in salt water. I have a grandduaghter who is only 5’1" and wieghs in around 90lb and she has no problems with them at all. Actually fit her better than the al80.
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I have 7 al 80’s and 2 are neutral 80’s I will not put them on my back I use them for filling lift bags. I use steel tanks to dive with, I have 2-80 4- 100 and 2- 120’s all are hp and all are din. I would never buy another alu. tank to go dive with they float when empty and are for beginner divers. And when was the last time you heard of a shop that could not fill a HP. Why carry all the weight of a lp when you can carry more air with hp.
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