Advice on tank purchase

[djnchels]

Hey gang!
My wife and I are ending our tour here in the middle east where we have been diving exclusively in the Red Sea using rental AL80 tanks. We have similar air consumption and average about an hour a dive without any problems. Now that we are returning home to Arkansas we will be diving almost exclusively in fresh water. I have read the pros and cons of aluminum vs. steel but would like some recommendations from fresh water divers as to what they would purchase? We are strictly recreational divers if that affects your opinions.
Thanks in advance! We are very much looking forward to getting back to the good ole' USA!

 

[Divin'Papaw]

I'm primarily a freshwater diver and I just purchased two Luxfer AL80s. My reasoning was (1) cost ... can get 2 al tanks for the price of 1 steel tank and (2) I dive with a wetsuit and not a drysuit, so the added weight of a steel tank at depth when you factor in wetsuit compression can be an issue. I like the fact that the AL80s are only 1.5 lbs negative when full since I loose a good deal of buoyancy between the surface and 60'.

When I buy a dry suit, I will also buy steel tanks at the same time.

 

[CompuDude]

For single tanks, the extra weight of the steel is usually considered a good thing, wet or dry. The situation where steel tanks and wetsuits could become an issue is when diving doubles. Single tanks it's generally no prob, unless there are some special fresh water considerations I'm not familiar with. I suppose I could also see the argument for someone diving in water so warm no wetsuit is needed. But single tank with a wetsuit is pretty much ideal, IMO. Less weight on the belt.

 

[hunter991]

I just got in some worthington 80's and they are slick....really short compared to a normal al 80.

Brent

For single tanks, the extra weight of the steel is usually considered a good thing, wet or dry. The situation where steel tanks and wetsuits could become an issue is when diving doubles. Single tanks it's generally no prob, unless there are some special fresh water considerations I'm not familiar with. I suppose I could also see the argument for someone diving in water so warm no wetsuit is needed. But single tank with a wetsuit is pretty much ideal, IMO. Less weight on the belt.

 

[Scuba Duba Doo]

I bought PST E7-120's last year diving in a 7mm +7 doubler with no issues while using a vest style BCD. I loved them. Trim was great and I only needed 6-10 lbs on my belt.

However, that being said, I did dive with them this year once with a steel back + wing and I was still negative without any weights while using a 3mm wetsuit. The Aluminum BP would have fixed the issue. Could be an issue at depths due to the wet suit loses buoyancy at greater depths (e.g. at 100FSW theoreticly a wet suit would only have 1/4 of its buoyancy).

 

[ChrisA]

First off if cost is a issue the AL tanks cost 1/3rd as much. Tha alone settle it for many people. OK assuming you can spend the money (because you are asking the question) then steel has a few advantages

1) It comes in more different sizes. You can match them to you needs

2) The total amount of weight on your feet is the weight the tank plus the amount of lead needed to sink the tank when it hold 500PSI. An AL80 needs maybe 5 pound of lead just to sink the tank. A typical steel tank neds negative one pound. So, with steel tank yu need 6 pounds less lead on the weight belt.

Weight only really matters to people who dive in cold water. In a 7mm wetsuit you might be using 28 pounds of weight and therefore be highly motivated to switch to a small, high presure steel tank and loos ten pounds off the belt. A tropical diver might be diving without a wetsuit and using only 6 pounds of weight and not be so motivated.

One example. If you only need 80 cu ft and you can get tanks filled at a dive shop (not a boat with a crappy compressor) then look at the steel 80ft tanks with working pressurs of 3442. These are lighter then an AL80 and very "nagative" you wil be able the shed maybe 6 or more pounds off your belts and a couple off your backs. It will make for an overall lighter rig.
This only matters if you have to walk down a trail to the water or if you are going into surf.
Another example would be if you both bought 100 or even 120 cu ft tanks. You can stay down a lot longer with all that air.

I have three sizes of stell tank 95, 80 and 72. It is goo to be able to elect the tank that is best for the dive. (but of course that tank is always empty so I have to take another.)

All that siad if the AL80 works for you you can safe a pile of money

 

[skyking]

I own a variety of steel (low and high pressure) and aluminum tanks. The addage of "right tank for the right job" is very accurate. What I've found is that my aluminum 80's get mostly used as loaners to folks who didn't bring enough tanks or when the fill station is closed or I haven't been to a shop lately to get the steels filled. Eventually the aluminums will get bands and a manifold. Generally I dive [the right] one of the steels, even in the late summer when the water here in Ohio gets warm enough to just wear a polartech 'cause the steels balance better and I like a light rig. A side benefit of the steels is that (at least mine) hold considerably more gas and with a good fill of 36 that makes for some long, relaxing quarry dives.

 

[Gator Diver]

First off if cost is a issue the AL tanks cost 1/3rd as much. Tha alone settle it for many people. OK assuming you can spend the money (because you are asking the question) then steel has a few advantages

1) It comes in more different sizes. You can match them to you needs

2) The total amount of weight on your feet is the weight the tank plus the amount of lead needed to sink the tank when it hold 500PSI. An AL80 needs maybe 5 pound of lead just to sink the tank. A typical steel tank neds negative one pound. So, with steel tank yu need 6 pounds less lead on the weight belt.

Weight only really matters to people who dive in cold water. In a 7mm wetsuit you might be using 28 pounds of weight and therefore be highly motivated to switch to a small, high presure steel tank and loos ten pounds off the belt. A tropical diver might be diving without a wetsuit and using only 6 pounds of weight and not be so motivated.

One example. If you only need 80 cu ft and you can get tanks filled at a dive shop (not a boat with a crappy compressor) then look at the steel 80ft tanks with working pressurs of 3442. These are lighter then an AL80 and very "nagative" you wil be able the shed maybe 6 or more pounds off your belts and a couple off your backs. It will make for an overall lighter rig.
This only matters if you have to walk down a trail to the water or if you are going into surf.
Another example would be if you both bought 100 or even 120 cu ft tanks. You can stay down a lot longer with all that air.

I have three sizes of stell tank 95, 80 and 72. It is goo to be able to elect the tank that is best for the dive. (but of course that tank is always empty so I have to take another.)

All that siad if the AL80 works for you you can safe a pile of money

""The total amount of weight on your feet is the weight the tank plus the amount of lead needed to sink the tank when it hold 500PSI. An AL80 needs maybe 5 pound of lead just to sink the tank. A typical steel tank neds negative one pound. So, with steel tank yu need 6 pounds less lead on the weight belt.""

I have never used a steel tank but I am guessing that even though you would
use 6 lbs less lead on the weight belt, you have the 6 lbs added to the wt. of
the steel tank. Wouldn't this put more stress on the back out of the water.
If the person who originally posted this question has back problems, wouldn't
it be better to distribute the 6 lbs on your weight belt and use an AL tank?
I have two AL 80s myself.

 

[CompuDude]

I bought PST E7-120's last year diving in a 7mm +7 doubler with no issues while using a vest style BCD. I loved them. Trim was great and I only needed 6-10 lbs on my belt.

However, that being said, I did dive with them this year once with a steel back + wing and I was still negative without any weights while using a 3mm wetsuit. The Aluminum BP would have fixed the issue. Could be an issue at depths due to the wet suit loses buoyancy at greater depths (e.g. at 100FSW theoreticly a wet suit would only have 1/4 of its buoyancy).

Not many places to dive in a 3mm suit here in the states. A few, but not many, so think about where you want to dive. Anything 5mm or thicker, and you'll benefit from the extra weight with SS.

 

[bradshsi]

I have never used a steel tank but I am guessing that even though you would use 6 lbs less lead on the weight belt, you have the 6 lbs added to the wt. of the steel tank. Wouldn't this put more stress on the back out of the water. If the person who originally posted this question has back problems, wouldn't it be better to distribute the 6 lbs on your weight belt and use an AL tank? I have two AL 80s myself.

Not necessarily. It depends on the amount of material used to make the tank. This in turn depends on the strength of the material and the design pressure.


For example the PST E7-80 has a buoyancy of -2.5 lbs empty compared to a typical AL80 which is about +4.4 lbs. The same steel tank has an empty weight of 28 lbs compared to 33.4 for the aluminum tank.

So not only can you save about 7 lbs from your weight belt, your back will thank you because your all up weight will be about 12 lbs less.


Now you know why cold water divers love steel



To answer the original poster's question, I prefer HP steel due to it's light weight, negative buoyancy and compact size. Factored over the life of the tank, the higher purchase cost is not a deal breaker IMO. Scubatoys currently has HP 80 tanks for $270.