Depends on if you can get overfilled or not. An LP85 at 3600 holds 116cu' of air. An HP100 holds what at 3600? 105'ish? An LP95 at 3600 holds 130cu' of air. And is smaller than an HP130.
HIGH PRESSURE TANK vs LOW PRESSURE TANKS...?
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Depends on if you can get overfilled or not. An LP85 at 3600 holds 116cu' of air. An HP100 holds what at 3600? 105'ish? An LP95 at 3600 holds 130cu' of air. And is smaller than an HP130.
LowDrag
Contributor
I just read an article in Dive Training magazine yesterday - March issue - that said an HP tank filled to capacity is harder on the first stage, SPG, and DC (obviously for those that are connected via HP hose). Also stated was that the size difference between most steel LP's & HP's was about 3/4" in diameter. Anyone know the accuracy of this?
It'll be harder on the HP seat, but I wouldn't worry about it unless you were pushing service intervals. I think (and someone can correct me on this) that everything that would be noticeably affected by this would be replaced in the annual service.
If you have unbalanced regulators, the larger pressure swing might be noticeable. I usually tune my regs at 3000psi, which meant I had a slow leak on an AL80N (WP 3300psi) the other day for the first few minutes of the dive.
False.
LP80s, LP85s, HP100s, HP120s are all 7.25"
LP95s, LP104s, HP119s, HP130s are all 8"
Most form factors have both LP and HP varieties. The original 3500psi E9791 tanks were all 7.25", but that's not true of the newer 3442psi exemption tanks.
LowDrag
Contributor
For nothing more than curiosity sake, I will have to do a little research on this. It will be interesting to see the differences. Thanks "A". 
OP
vcblklion
Contributor
Just curious. The DIN/Yoke valves...don't they tend to leak where you screw the adapter in? I would think that would be a primary fail for that kind of valve.
LowDrag
Contributor
I found these spec's at Dive Gear Express's website: http://www.divegearexpress.com/library/tanks.shtml
When I was doing my pool and open water work I never saw anyone with a leaky connection. It explained to us in our class that you lightly tighten the yoke to the valve on the tank and that when you open the valve the pressure would lock the yoke to the valve.
| Cylinder | 2640 psi | 3000 psi | 3442 psi |
HP Steel 80 64 cu. ft. 72 cu. ft. 80 cu. ft.
HP Steel 100 80 cu. ft. 89 cu. ft. 100 cu. ft.
HP Steel 120 96 cu. ft. 107 cu. ft. 120 cu. ft.
HP Steel 119 95 cu. ft. 107 cu. ft. 119 cu. ft.
HP Steel 130 104 cu. ft. 117 cu. ft. 130 cu. ft.
HP Steel 100 80 cu. ft. 89 cu. ft. 100 cu. ft.
HP Steel 120 96 cu. ft. 107 cu. ft. 120 cu. ft.
HP Steel 119 95 cu. ft. 107 cu. ft. 119 cu. ft.
HP Steel 130 104 cu. ft. 117 cu. ft. 130 cu. ft.
| Height | Tanks |
| 17 Inches | HP65 |
| 20-21 Inches | AL63, LP66, HP80 |
| 24 Inches | LP80, LP95, HP100, HP119 |
| 26 Inches | AL80, AL100, LP85, LP104 |
| 28-30 Inches | LP120, HP120, HP130 |
| Diameter | Tanks |
| 6.9 Inches | AL72, LP85 |
| 7.25 Inches | AL63, AL80, LP80, HP80, HP100, HP120 |
| 8 Inches | LP95, AL100, LP104, HP119, LP120, HP130 |
When I was doing my pool and open water work I never saw anyone with a leaky connection. It explained to us in our class that you lightly tighten the yoke to the valve on the tank and that when you open the valve the pressure would lock the yoke to the valve.
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Herb-alaska
Contributor
You are correct however I fill at the Fire Dept that I am a member of and they are hardliners for the rate pressure only . So no over fills happening there
I have hundreds of dives using my single HP100 tanks (Faber FX series with pro-valve). I use them in the yoke config since my recreational reg is still yoke, and I've never had a problem with a leak or anything else with them. I replace all of the the o-rings & service the valves when I VIP them annually.
We have Pro valves on a number of our tanks. We use them as DIN, and students usually use them as yoke. Never had a leak. The inserts use the same sealing system as a DIN regulator, so I don't know why they would be any more prone to leaking than a regulator would be. (Both will leak if the o-ring is damaged or missing.)
elan
Contributor
I would not rush with hp100. Try other tanks.
Depending on the make and your height they can be aweful or can be awesome.
Xs hp100 have a great weight to volume ratio and great buoyancy characteristics but thie trim characteristics for taller people suck as they are short.
If you only dive singles they are ok but if you will look into doubles later you have to consider you height.
I had hp100 and sold them for reasons mentioned above.
If I was buying the tanks again I would go with faber lp85. Thats the best tank I have found so far for the rec. Its easy to fill it to 3000 and it holds about 95 cuf. Its light and not buoyant as al80
The issue with hp is you have to pump them to 3800-3900 to get 3500 at rhe end. Not many shops would do that even if they have an ability. Here they usually fill them to 3500 and top them up and thats takes a lot of time.
I hated hp tanks because of that and got rid of all ofthem
Depending on the make and your height they can be aweful or can be awesome.
Xs hp100 have a great weight to volume ratio and great buoyancy characteristics but thie trim characteristics for taller people suck as they are short.
If you only dive singles they are ok but if you will look into doubles later you have to consider you height.
I had hp100 and sold them for reasons mentioned above.
If I was buying the tanks again I would go with faber lp85. Thats the best tank I have found so far for the rec. Its easy to fill it to 3000 and it holds about 95 cuf. Its light and not buoyant as al80
The issue with hp is you have to pump them to 3800-3900 to get 3500 at rhe end. Not many shops would do that even if they have an ability. Here they usually fill them to 3500 and top them up and thats takes a lot of time.
I hated hp tanks because of that and got rid of all ofthem
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