# High or Low Pressure tanks?



## jer4011 (Oct 6, 2007)

Just wondering what most people prefer and why. I dive with one of each right now. I like the size of the high pressure better but I usually get a much better fill on the low pressure tank. The HP usually ends up a little short by the time I get it to the boat and the LP is usually filled a little over.


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## CootCommander (Aug 24, 2008)

I have 2 hp 130s right now. They're a couple inches taller than an Lp 108 but obviously have more capacity. A lot of people recommend LPs bc they are faster and easier to fill, however my Hp 130s have a volume of 104 under filled at 2640 psi and 117 under filled at 3000 psi. I usually drop off my tanks and pick them up later in the week before my next dive so time is really no factor to me.


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## FenderBender (Oct 2, 2007)

I like al 80s. All that extra air and bottom time would get me in trouble. I'm an air sipper, though.


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## Firefishvideo (Jul 1, 2010)

Steel low pressure 95's are my first choice. Plenty of gas....especially when you can usually get them filled to 3000psi. The HP tanks are smaller, but they are heavier under water (negatively bouyant) ....since I use no weight with the 95's ......if I were to use HP tanks I would have to add air to the bc....which would be inefficient and cause drag/use air. I don't notice the extra bulk underwater, and the dive shops like the LP tanks better because they are easier on their equipment.
You can acutually buy new tanks the same size as the 95's that have had the pressure rateing raised to 3500psi .....which gives you an insane amount of gas.


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## SaltAddict (Jan 6, 2010)

I just picked up 2 lp108s. I use 12 lbs of lead with an al80 and a 3mm wetsuit (14lbs with a 5mm). The 108s are 14.5 lbs heavier than al80s. I'm sure I will need a little gas in the bc while in a 3mm. However, at a 20ft safety/deco stop with an al80 I have trouble staying down. Can't wait to get the 108 wet and see how it trims me out at 20ft.


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## jer4011 (Oct 6, 2007)

Firefishvideo said:


> You can acutually buy new tanks the same size as the 95's that have had the pressure rateing raised to 3500psi .....which gives you an insane amount of gas.



Scott, This is Jeremy from Mark's boat. How would you go about getting the pressure raised on a tank? Is that something they would do during the hydro or do you need a new valve for the tank?


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## jamesw21 (Feb 26, 2011)

Can't change the service pressure on a tank.


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## Firefishvideo (Jul 1, 2010)

I didn't mean you could change a current rating ....just that the new tanks are the same size....effectively 95 cubic foot tanks.....but they are rated to 3500...I Don't recall what the final volume is..... Clint has one, you should talk to him about it. Same tank , just higher rating......these tanks were always capable....just not rated.


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## sealark (Sep 27, 2007)

jamesw21 said:


> Can't change the service pressure on a tank.


Just purchase your own compressor and fill them to what you think is needed and safe.:thumbup:


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## WhackUmStackUm (Jan 31, 2010)

sealark said:


> Just purchase your own compressor and fill them to what you think is needed and safe.:thumbup:


+1 - That's what I do. :yes:

FYI - I recently switch from 3500 psi *steel* tanks on my rebreather (19 cf) to 4500 psi *carbon fiber* tanks (21 cf). My rebreather setup now weighs about 10 lbs less when I am schlepping it around. However, I now have to add an extra 8 lbs of lead weight before jumping off the boat. It is an acceptable trade-off for me.


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## jer4011 (Oct 6, 2007)

I think I am going to look for another LP 108... A compressor is a little more than I am wanting to spend right.


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