Things to know before buying tanks

[GrumpyOldGuy]

All the advise is greatly appreciated.

let me show some of you what I'm reading -
From - Dive Tanks | LeisurePro.com

The LP info contains a lot if miss-information with some valid info. The post by UNCFNP contains the valid points in a much more compact form.

Case in point, the DIN/Yoke thing. Most decent valves have converters built in now. It's a non-issue on the tank.
Also, the lifespan of any new tank you purchase will most likely exceed your dive career. I still have a 1981 US divers tank, still works. Steel will last longer in theory if no rust, but once you have a product with a 25+ year life cycle the point is moot.

 

[SVT_Tactical]

Thanks guys. Seems like those might be a good ideal. I could always buy a DIN 1st stage for those and use the yoke for my pony bottle setup I have yet to get a setup for.......

 

[herbdb]

Steel tanks will allow you to reduce the amount of weight you carry, but only because the tank is heavier.

I dive steel 120s at home in cold water (thick wetsuit) with 8lbs of weight. I would have considerably more weight with an AL tank.

I think this is an advantage because it keeps me from wearing a really heavy weight belt or over stuffed BC weight pockets. It is more comfortable, has better balance and gives me plenty of gas.

If you can, rent or borrow and try before you buy.

 

[redacted]

Steel tanks will allow you to reduce the amount of weight you carry, but only because the tank is heavier.

To be clear, it is not that steel tanks are necessarily heavier; but that they are less buoyant. For example, a Luxfer AL 100 weight 41 pounds while an E7-100 weights 33 pounds and that E7-120 comes in at 38 pounds. But their buoyancy (empty) is 3 lb, -1.2 lb, and 0 lb respectively. That means you will need to carry an additional 4 lb of lead when you use an AL 100 rather than an E7-100.

 

[SVT_Tactical]

Another into the mix... being tall 6'6" should I try to get larger tanks to better balance out my weight or will there be negligable difference in the 100's to 120's as far as being able to trim well and not feel all the weights trying to slide up to my head.

 

[redacted]

Another into the mix... being tall 6'6" should I try to get larger tanks to better balance out my weight or will there be negligable difference in the 100's to 120's as far as being able to trim well and not feel all the weights trying to slide up to my head.

A 120 may be just what you need. You may have trim problems with shorter tanks.

Scuba Cylinder Specification Chart from Huron Scuba, Ann Arbor Michigan

 

[uncfnp]

The 100's are almost the same length as the Al 80's so if you are ok with the length in Al 80's, trim should be fine in the HP 100's (you may have to redistribute your weights some) but at that height you can definitely handle 120's and you'll get more bottom time. As an "air hog" lets say your SAC rate is 1. That means at 75 feet you will get about 6 mins more bottom time with the 120's if my math is right. And that difference will increase as you relax and your breathing improves.

---------- Post added August 23rd, 2013 at 12:25 PM ----------

But as a downside, some shops will charge more to fill them, especially nitrox...

---------- Post added August 23rd, 2013 at 12:32 PM ----------

Also plan on loading and unloading the 120's on your own. Nobody is going to help you with those puppies .

 

[kelemvor]

Also plan on loading and unloading the 120's on your own. Nobody is going to help you with those puppies .

If he's a good tipper, and dives multiple trips with the same op... anything's possible! By trip two with Rainbow Reef in KL the op was coming to my car to haul my steel 108's down onto the boat for me. I don't even think I'm a particularly high on tips - the boat gets $20 and if I dive with a guide, they get $20.

Most ops haven't charged me extra for nitrox in my steel tanks, but one op charged me $4 extra a fill (Silent World, Key Largo FL).

 

[tech3324]

It's hard to go wrong with a plain old steel 72 as your first tank. They are cheaply and readily available, last pretty much forever, and have good bouyancy characteristics. You can always add another tank later after you've been diving for awhile and know exactly what you want. In my case, other tanks have come and gone, but I still use a steel 72 dating from the 1960's and bought used.

 

[eelnoraa]

Another into the mix... being tall 6'6" should I try to get larger tanks to better balance out my weight or will there be negligable difference in the 100's to 120's as far as being able to trim well and not feel all the weights trying to slide up to my head.

For you height, I also suggust HP120. It is a long tank, longer than AL80, and a lot long than HP100.

The 100's are almost the same length as the Al 80's so if you are ok with the length in Al 80's, trim should be fine in the HP 100's (you may have to redistribute your weights some) ...

I disagree with this. HP120 is longer than AL80 by about the same amount AL80 is longer than HP100. On paper, each is different by about 2". In real world use, the difference is very noticeable.

All 3 trim very different too. HP100 is short and negative empty. It is good for diver that is leg heavy, especially for tall divers. HP120, due to its length, it makes trim easier for head heavy divers. AL80 is kind of in the middle. But of course, with single tank, one can do a lot with postrure and solve trim issue especially with drysuit, in that sense, they all trim similar.