Tank Purchase Questions

[Trader Will]

I'm just now getting into diving. I have some of my gear already and it includes an 80 cu ft aluminum cylinder with a K valve. My instructor thinks I should definitely get a second tank, he thinks it should be steel because the extra weight will mean having less lead to carry.

I was thinking since aluminum is much cheaper, and I already have one aluminum 80 that I should just get a second aluminum 80 so my weight setup will be the same.

Right now I'm looking at a new sherwood 80 for 189.00 or possibly a new steel 77 that is 225.00 or a new steel 85 that is 269.00

What do you guys think? I'm leaning towards the aluminum.

 

[101recon]

My instructor thinks I should definitely get a second tank, he thinks it should be steel because the extra weight will mean having less lead to carry.

I was thinking since aluminum is much cheaper, and I already have one aluminum 80 that I should just get a second aluminum 80 so my weight setup will be the same.

I chose a 2nd identical (AL80) tank so that my rig would stay the same when changing tanks.I didn't want to have to adjust weight between dives.As a new diver developing my buoyancy skills,I felt it would be easier for me if my weight didn't change on each dive.

Maybe one of our more experienced divers can shed some light on the steel tank/less lead to carry thing.I understand that a heavier steel tank will require less lead,but the total weight remains the same.Whether it's 5lbs steel + 5lbs lead OR 6lbs steel + 4lbs lead,you are still carrying 10lbs. Other than different weight distribution affecting trim,I don't see the advantage.

 

[SailNaked]

buy steel they last a lifetime. AL is about 10-20 yrs. or buy AL they are lighter, Or buy steel they do not require weight at the end of the dive because they are always negative. or buy AL they are cheaper. buy steel they are available in more sizes and larger. Buy steel you can overfill them. buy steel you can get LP or HP.
Buy AL they can be painted pretty colors. I give up thats it for now.

If you buy steel, they come in different sizes so if you do not want to adjust your tank bands on your BC every time then get the same diameter.

 

[Rick Inman]

Where, and what kind of diving are you doing?

If you live and dive in the Fl Keys and just use a shortie, the AL80 is a better choice than the steel. If you live in Alaska, you'll want the steel tank to take some weight off your hips and put it on your back.

You want to match the right tank for the right kind of diving.

My first tank was an AL80, but a better choice for me would have been a steel 95. So when I bought my 2nd tank, I didn't repeat the mistake just so I could match. I bought the better tank and moved forward.

 

[cbrich]

I have both steel tanks and aluminum tanks. A HP100 steel tank is the same weight as an aluminum 80, and it's smaller. I trim out better with my steel tanks than I do with my aluminum tanks.

I would say get another aluminum tank because adjusting weight between dives could be a pain, unless you want to carry around 2 weight belts, 1 for aluminum tank and 1 for the steel tank. I can think of several different ways to adjust your weight for aluminum and steel tanks.

Before you buy try diving with a steel tank, and another dive with your aluminum tank.

 

[GrumpyOldGuy]

I chose a 2nd identical (AL80) tank so that my rig would stay the same when changing tanks.I didn't want to have to adjust weight between dives.As a new diver developing my buoyancy skills,I felt it would be easier for me if my weight didn't change on each dive.

Maybe one of our more experienced divers can shed some light on the steel tank/less lead to carry thing.I understand that a heavier steel tank will require less lead,but the total weight remains the same.Whether it's 5lbs steel + 5lbs lead OR 6lbs steel + 4lbs lead,you are still carrying 10lbs. Other than different weight distribution affecting trim,I don't see the advantage.

Actually, a high pressure steel tank of the same size will weigh less. Steel is a stronger and denser metal, thus the walls are thinner and the water displacement of the tank is smaller.If you compare a HP100 vs an AL80, the steel tank weighs less, ALSO allows 5lbs less lead and hold 30% more air.

Steel tanks are awesome, but I still have 6 AL80s that see a lot of use. They give you great bang for the buck and the 3000psi fill is standard.

If you have the money, you can't go wrong with an HP100. You can add a weight pouch on the cam band to hold a 5lb weight to make up the difference. If you are tight (like I am normally) then stick with the AL80. They get the job done just fine.

 

[rstofer]

You should really fill out your profile...

If you dive warm water, an Al 80 is fine. I have 2 of them and, as I now dive cold water, they are never used.

If you dive cold water, an HP100 is a great choice and you can take 6# off your weightbelt. I have 6 of them.

But an Al80 usually costs $150 and an HP100 is usually around $300 so, if you don't mind carrying an extra 6# (and can add it to your cambands), you can save a few bucks with Al 80's. You can also sell your Al 80 to paint-ball players.

Luxfer Al 80s have a rated life of 100,000 cycles. If you refill twice a day, 365 days per year, you should think about replacing them in 136 years, give or take. I'd be willing to bet that a steel tank will be a rusted out hulk long before that. The real fact is that nobody knows how long a tank will last. One of my Al 80s is 22 years old and in perfect shape, the other is 15 years old and also in perfect shape. HP steel tanks haven't been around long enough to know how long they might last. LP steel tanks seem to last forever. I have one that is over 40 years old.

Short answer: cold water -> HP 100, warm water -> Al 80

Richard

 

[rstofer]

Another thing: if you buy steel tanks, keep that Al 80 unless you get a really good offer. It's a sunk cost at this point.

There are a lot of times when you just want to test your reg, inflate your BC (although oral inflation will work) or just fool around with your gear and a tank full of air is handy. All of my tanks steel tanks are stored full of Nitrox. When I need to mess around, I just use air from an Al 80 and keep my main tanks ready to go!

Richard

 

[Trader Will]

I live in Jacksonville, FL., so the bulk of my diving will be in subtropical and tropical conditions.

The aluminum 80 I have now is a catalina, got it off craigslist with some other equipment, never used, filled with air. The guy was supposed to go on a month long vacation to the keys with his parents, but he didn't go. The tank has a sticker on it that says enriched air ready, so I want to get a second aluminum that will take nitrox, I realize now the Sherwood does not, but the tank that's 60 bucks more does. (scuba.com)

Aluminum tanks require more weight at the end of a dive? I'm 5'10" and I weight about 280, I'm pretty muscular from lifting weights, but I do have a fat gut. Do you think that will affect my buoyancy due to water displacement?

I want to get good value for my money. I'm not opposed to spending more on a steel tank, but I don't want to if I don't have to. Do all dive shops rent tanks? Maybe I can put my second tank purchase off till I know better what tank I want? How come a 3000 PSI standard fill would be a +? Is that for filling reasons at the shop? If I were to purchase a steel tank to go with the 80 aluminum that I have now,what size should it be?

Between a 95 nitrox steel, or a 100 nitrox aluminum which would be better to go with my 80 nitrox aluminum? Or maybe a 108 nitrox steel tank?

Thanks for the responses.

 

[GrumpyOldGuy]

I think renting is a good idea for you. Being a big guy, you may find you use more air than your buddies and that may drive your decision down the road for a larger steel tank. Renting tanks is easy and cost effective for many.