Rich asks…Why are you diving with that Tank?

First off, I am going to do a quick intro here. Hubby Rich as many of my followers know is OCD about the equipment. I love him and never have to worry about things going wrong. With that said, where my experience and love comes from learning more about creatures, he is the one who seeks out everything about equipment, gadgets, tech tips ect. Kind of a Ying and Yang thing going on between us. Works perfect I might add. So I will be doing some Rich spotlight topics. Mind you I learn about these as he gives them to me, but I am just not as good or as inclined as he is with the logistical, technical (boring) side of things. LOL.

So…Why are you diving with that tank?
by my fabulous husband Rich

We all learned to dive on good old faithful AL 80’s (aluminum 80). But just because it is familiar, does it make sense to continue diving with it? It’s a question I asked myself and below you will find my reasoning that I came to and the tanks I purchased. If you are interested read on, if not go and read Danielle’s creature features.

Standard 3000psi, has been around since 1970’s
Not much has really changed
It’s cheap about $150 for a new one
No rust issues
Heavy weighs 31-32 pounds
Tall 26″
Bad buoyancy issues
1.6 negative when full
2.8 positive when near empty at @500 psi
@500 psi bottom of tank is more buoyant and it will tend to tip your head forward and your butt up.
@ 3000psi you get only 77.4 cubic feet of gas.

Now let’s talk steel tanks.

You can choose a High Pressure (HP) steel tank or a Low Pressure (LP) Steel Tank. The HP appears to be much more popular. (not that I really care what the masses are doing, saying or recommending). Everyone likes the HP steels over LP steels because you can get more air in a smaller tank. The main argument I found in favor of LP steels was that they said not every dive shop could fill HP tanks but all can do LP tanks. That is the dumbest thing I have ever heard and I chortle to myself every time I hear that reasoning. Just go to a dive shop that can do it for you. We have 4 LDS we use frequently and locally and all of them do HP fills. So…end of my interest in the LP steel tanks.
Now, I have chosen High pressure steel tanks (HP) so let’s go over the 4 main size choices; HP 80, HP 100, HP 120, HP 130. The manufacturer I will examine is Worthington by XS Scuba, generally regarded as the best on the market. They are what I buy and a little birdie told me wife is surprising me on Sat with one from our friends at Gold Coast Scuba.
Worthington tanks utilize the ‘Deep Draw and Ironing’ (DDI) process. They start as a circular plate of chrome-moly steel, multiple draws on a hydraulic press turn the plate into an open ended shell, which is when it starts resembling a tank. The shell is then closed, and the neck and threads are formed. The DDI process gets consistent, reliable results every time making every tank the lightest, most efficient cylinders possible. As a result these canisters have THE best buoyancy characteristics possible for scuba diving.

The Worthington tanks are coated in a 8-10 mil layer of zinc. Not painted on, but a metallurgically bound barrier protecting your tank from the corrosive ocean environment. It will NOT chip, or flake away like a painted on finish. This will give add years to the durability and effectiveness of the tank overall. Worthington also offers a lifetime guarantee on the exterior of the cylinder. If the exterior rusts, or has any problems they will fix it for you for free. You can’t find many manufacturers who are willing to do that for you, especially for free.

Cylinder Specs: (wife yawns at this point)

Steel Tank Chart

I know you are all asking yourself…WTF does all those figures mean to you in the water?
First ask yourself these questions?
Who do you dive with? Is it the same person all the time, do you change dive buddies frequently, do you dive with men or women?
Are you an air hog?
How physically strong are you?
Do you want as much bottom time as you can get? (WINK WINK) Who doesn’t?

    so let’s compare AL 80 to HP 80

HP80 is:
6.5″ shorter
4 lbs lighter
5.8 lbs less buoyant @500 psi

so you need less weight…6 lbs taken off your weight belt or out of your BCD integrated weights.
You get more air…3.6 cu ft of air extra.
In all actuality, you are 10 pounds lighter with the HP 80 over the AL 80. Stay with me. (4 lbs off tank plus 6 lbs off weights)
Plus you get 5% more air with the HP. And it is a more comfortable dive with a shorter tank.

    If you want significantly more air, let’s take a look at AL 80 vs HP 100

HP 100 tank is 2″ shorter
1 pound heavier
negative 5.3 less buoyant @500psi

so you need 5 pounds off your weight belt
You get much more air  about 22.10 cu ft of extra air

in the end you are 4 pounds lighter with this tank over the AL 80. (-5 off weights +1 for tank weight)
29% more air and a shorter more comfortable tank.

Now…still need more air (me too!)  AL 80 vs HP 120

Tank is 2″ taller
6 pounds heavier
-4.8 lb less buoyant @500psi

so you need 5 lb off your weight belt
You get much more air. For us air hogs that is a good thing. 43.20 cu ft of extra air!
You will be 1 pound heavier (-5 for weights +6 for tank weight)
You get 56% more air. For only 1 pound of extra weight and extra 2″ of tank I gain so much more air. That is a win win for me.

Lastly let’s look at AL 80 vs HP 130 (overkill?)

tank is .5″ shorter
3/4″ fatter with 8″ diameter
11 lbs heavier
-4.8 less buoyant @500 psi
you still need 5 lb off your belt.

therefore you are +6 lbs heavier in the end by choosing this tank (-5 for weight +11 for tank)
Loads more air…70% with 54 cu ft more of air.
IMHO it is a fat heavy tank but if you have to have the extra air, it’s a viable option. I would be concerned that the extra tank width might cause you problems on boat tank racks.

My choice in the end for Danielle and myself was:
HP 100 steel for Danielle. She is a good swimmer but at times has buoyancy issues. Never really pays attention to how much weight sshe needs with what suits she is wearing or not wearing. This tank is 10 pounds less weight for her to dive with. Great for her as she does not have the same upper body stregth as I do. On beach dives where you may have to trek a bit to the water this is very important. Plus she gets 29% more air which is longer bottom time making it so we can relax and see more. Add the fact the tank is 2″ shorter so it is more comfortable on her back. Want the little lady to be as comfortable as possible.

For myself I went with the HP 120 steel. I dive only with my wife as my dive buddy. I am an air hog and strong like bull. I’m not as worried about the weight I have to carry down to the shore but it’s only 1 pound more than the AL 80. It gives me loads more air than Danielle and it even’s out my air hog issues a bit. I now do not have to listen to her moan as much about how much air she has and that she hates to waste it. This is important as we can enjoy equal dive time and come up with same air left.

The only thing I think the AL 80 have going for them is the price. They are 1/2 the price of the XS Scuba steel tanks but I think well worth it for the 20 plus year tank life.
If you are renting tanks, try out the steel tanks next time. I promise you will be hooked.

About daniellesdives

diving enthusiast
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10 Responses to Rich asks…Why are you diving with that Tank?

  1. Brian says:


    Excellent article on tanks. I want Steels and keeping an eye out for some used ones. Many may go ‘why buy used’, well, for steel tanks it’s not that much of an issue if they have been cared for. There are MANY stories out there of Steel 72’s still in service and passing hydro etc. Going rate depends on the area, but usually $200-250 for used Steels in the 100-120 CF range.

    Also, really great way at going with the whole weight issue for lead. Never sat down and figured this out (never had steels, and shops around here only rent AL).

    • Hubby has a big list of people with used. He was gonna buy used but I wanted to get him a new one for belated birthday. Too cold still for the shorty front zip suit he wanted. I was ask him if he wants to share with you. I know he wants to pick up two more but he has been having communication with a couple guys. A few guys have lots of three they do not want to split. He is finding them for $600 for three tanks. I will let you know. What size you looking for and how many, perhaps if we only need a few you can piggy back on the deal for the extra?

  2. Brian says:

    Right now, working on my BP/W and Bottom Timer. I appreciate it though. I wont be looking for ones til around new yearish (maybe earlier). Also, if I can get into this new apartment will free up about $340/mo.

  3. Brian says:

    Yes, pretty much will tell me Max depth, current depth, time under water, and some of them even give a temperature reading.

  4. Tubbyman says:

    Excellent post! I’m definitely an air hog too (and not worried about weight) and will certainly look into getting larger tanks when buying my own. Is it your experience that larger tanks are available for renting generally as I have only ever been offered a size upgrade once. Thanks for the info!

    • are you in Florida? For LDS we use 4 on a regular basis and most are available there. Wife bought me a new tank I am picking up for this weekends dives in LDBS but she rented a 100 steel there they are holding for her and they have one 120 for rent as well. Find good dive shops, don;t settle for inferior mass market chains, they tend not to care about you for the long haul. Gold Coast in LDBS carrieds Worthingtons beacsue we asked and gave him the info on it. He has done well with them

  5. Brian says:

    When I had a Dive Computer I just ran gauge mode and was really sweet. I hated the built in compass though, just feel much better with a traditional compass than a computer one.

    If I could afford one, I’d love to grab a Liquivision Axiom, but they are very expensive. And a lot of the cost is the OLED they use.. Hoping to find a Xen bottom timer used though. Very easy to see screen.

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