Choosing a steel tank to purchase

[marginwalker]

New diver here looking to build out my gear. I'm 5'11" and 165# and will mostly be diving Monterey, CA in 7mm wetsuit. I've already pulled the trigger on a BP/W from DGX, and now I'm shopping for a computer and regulator set. But since my BP/W arrived yesterday, I am looking to get it set up, and it occurred to me that getting to a point where I am consistently using the same size/type of tank will be useful to dial in my weighting/buoyancy/trim.

So now I think I should probably be shopping for a tank sooner than later.

I think I want a steel tank so that I can carry less lead, and I am also a bit of an air hog so not sure exactly what size tank I should choose. I realize my gas use will improve with experience (it already has gotten better as I've relaxed and had better trim on the last few dives) but I'd like to better understand the various choices in steel tank sizes.

What are the real practical differences between the LP85, HP100, HP120?

What advantages or disadvantages are associated with choosing an 8" diameter tank like the HP117 and HP133?

Feel free to answer these questions or offer any other advice you think someone on my position should consider. I've already reviewed the various dimensions, dry weights, full/empty buoyancy of all of these tanks, but some advice about how those numbers might affect my diving would be very much appreciated. Thanks in advance!

 

[johndiver999]

If you are very strong and are diving from a boat, then having a larger, heavier and higher capacity tank may be a good choice. If you plan on shore diving or having to carry the tank any considerable distance, then a smaller lighter tank is better, also if going through a surf break, over rocks etc.

If you want to optimize your tank, then you have to define the application. If you are new and can't really do that... then rather than buy a tank.. make a dive buddy, preferably one who has a few tanks and will dive with you. It is not much of a burden to loan a tank to a buddy, especially if he will be responsible for getting the loaner tank and the owner's tank filled.

Looking around what other locals use for the type of diving you expect to do, is a good idea.

 

[RyanT]

Forget the LP85. It's lighter than other steel tanks and unless you can get it overfilled (unlikely) it's capacity isn't going to be that great. 120's are ridiculously long. At 5'11" you'll find it's a problematic fit when sitting on boats, etc. The HP100 is a really nice tank. Decent capacity and it remains a tad negative when empty. This will be nice given how much rubber you're wearing. The bigger, 8" diameter tanks are nice in terms of capacity, but the additional girth means that your trim will be a little less stable compared to 7.25" tank. It's not a huge deal, but likely to be noticeable.

 

[elan]

LP 85/Faber HP100 would be good for your height as a single. If tou decide to double them up later Hp100 I find might be a bit short. 120 ies are tall IIRC 28 inch
Going 8 inch tanks means more air but heavier. As your SAC rate drops you might find they will be too much for one dive but not enough for two.

 

[elan]

The bigger, 8" diameter tanks are nice in terms of capacity, but the additional girth means that your trim will be a little less stable compared to 7.25" tank. It's not a huge deal, but likely to be noticeable.

Ryan if OP decides to go with BP/W this will be a non issue. I routinely dive with an AL80 stage on with a single AL80 on the back and sometimes for training add another and it is not an issue with two AL80ies on one side.

 

[Thunder Struck]

I’m looking at the Faber 117 for my next tank. I normally run the LP95, but for just a scooch more length and less than 2lbs heavier. The 117 ft^3 rating is at 3442 psi, and at 3000 psi that works out to about 102 ft^3. It’s also slightly more negative than the LP95 when empty. Even though the LP95 is technically 1.7# positive when empty, in most cases there’s still going to be at about 500 psi near the end (about 1#) plus there’s a couple lbs to add for the valve.

Check the tanks on this site, find out what you want in terms of specs and see what fits your requirements: SCUBA Cylinder Specifications

 

[Eric Sedletzky]

I would get a steel HP100 3442 E7 7.25” diameter.
It’s about the best all around tank for California beach diving. And boat diving too.

 

[Scraps]

I did the Goldilocks routine with my steel tank purchases, eventually getting to where @Eric Sedletzky recommends you go.

First I bought a pair of 80's--Too small. Nice, compact size, but I need to have enough air to set the anchor, dive with the longest breathing customers, return to depth to clear the anchor--and have reserve for any other contingency that arises. Ultimately, it's too small. Now I mostly use them when I'm teaching OW classes in a shallow lake.

Then I bought a pair of 120's--Too big. Plenty of capacity, enough that I kept getting them re-filled when they still had 1500 PSI in them. They're not too big for me to dive with--I'm 6'4" with a long torso, and they're comfortable underwater. But it seemed like a lot of extra effort to carry such a heavy tank to and from my truck when I know I'm unlikely to use 2/3 of the gas inside. Now I use them mostly for spearfishing in deeper water.

Finally, I bought a pair of 100's--Just right! These now are my favorite go-to tank. Normal size. Plenty of capacity for all but extended deep dives.

 

[rob.mwpropane]

I have steel HP80, LP85, HP100, and HP120's.. I can't tell any real difference between the 85 and 100's diving them. I do think that the 100's are better just because it's more gas if you can't get the 85's filled higher.

I have more steel 100's than anything else.

 

[Divin'Papaw]

The HP100 is a really nice tank. Decent capacity and it remains a tad negative when empty. This will be nice given how much rubber you're wearing.

I would get a steel HP100 3442 E7 7.25” diameter.
It’s about the best all around tank for California beach diving. And boat diving too.

I have steel HP80, LP85, HP100, and HP120's.. I can't tell any real difference between the 85 and 100's diving them. I do think that the 100's are better just because it's more gas if you can't get the 85's filled higher.

I have more steel 100's than anything else.

Finally, I bought a pair of 100's--Just right! These now are my favorite go-to tank. Normal size. Plenty of capacity for all but extended deep dives.

Ditto to what these folks have said. Go with the HP100s. They are the ideal tank for most people especially for cold water. We see them a lot here in FL too. I own 4 HP100s myself.