Tanks

[St_Augustine_Diver_62]

Im looking to buy a tank need advice i want the most i can get out of tank for as most capacity i was told its not just psi its cubic foot capacity is this true whats a good recommendation for as most air for diving and steel are aluminum ?????

 

[terrasmak]

Alum 80's will probably be fine for you for tropical waters and steel 80's if you dive cold water . I would say 100's are probably the biggest you should go in either metal. If either of those end up being to small , doubles . Something to remember the bigger your air supply , the more trouble you can get into . Twin 80's can easily put you into deco diving at 60 feet. Depending on your training, your more time limited, than air limited .

 

[tribaltim]

I love my Steel 80's....

 

[aabond]

I love my steel HP 100's by PST. It's a few inches short than an aluminum 80 and packs in 25% more air. Not to mention you get to shed a few pounds of lead. Most of my diving is in southeast florida, and right now with water at 73 F i'm diving a 3mm full. Great tanks!!!!

 

[DiverBuoy]

It's about cubic foot AND about PSI for a number of reasons. For example you might get more capacity (cubic feet) in a smaller package by having a high pressure cylinder, however depending on the working pressure rating (the max PSI of the tank) some scuba shops don't have compressors capable of filling a High Pressure tank full, so you'd have this great tank that's only getting filled to say 85% of it's capacity. Also HP tanks require different fittings on your regulator typically DIN mount vs yolk mount for LP tanks. There are adapters of course to use both kinds of tanks. Yet another alternative is an LP tank with lot's of capacity but then the tank is "very" tall and this can be an issue for a shorter person, or may present trim problems. Additionally some older BCs may be inadequate to provide the necessary lift compensation for really large or heavy tanks.

Sorry but these things are never completely simple. Why not tell us the type of equipment you have like regulator (yolk vs DIN) and the BC you dive (BP/W? Jacket Style? Single tank? Dual tank?) and the type of diving you are planning to do and we can be more specific.

Here is a bit older post about different types of tanks:
http://www.scubaboard.com/showthread.php?t=17898

 

[spectrum]

I'll ditto the steel suggestion

First, it is the Cubic Foot Capacity (CF) that you need to consider for evaluating the amount of air a cylinder contains. The pressure only determines what size package the air is stuffed into.

So what size cylinder do you need? You don't wan't to lug more air than needed. There is a point where you will be burning air just to lug the air and get yourself worn out above and below the water for nothing. There' not much in your profile (HINT) to go on so here are a few general thoughts...

* Assuming you have been diving for a while do you know what size you need? In some cases it means understanding what sorts of dives you are planning to do and doing the planning based on your personal SAC.

* You can also go relative to fellow divers. If you have a circle of buddies that you dive with you can go from there. Lets say you all dive 80 CF tanks right now but you are always the first to turn the dive for low air, then consider a 100 CF cylinder.

One of the biggest advantages of steel cylinders is the weight implications. A high pressure steel cylinder will weigh less per CF capacity. This will make life easier hiking across the beach and you will have less inertia underwater. This is true for any diver.

The second advantage of steels are the buoyancy properties. You are already wearing some weight to sink youf exposure suit. An aluminum 80 is about 4.4 pounds positive when empty. That means you need to strap on 4 more pounds of lead just to hold it down near the end of the dive. Since most steel cylinders remain at least a few pounds negative they actually contrubute to holding you and your suit down during the dive, letting you remove a few more pounds from your belt. For warm water divers with thin wetsuits the weight reduction is much less of a consideration compared to some cold water divers that may need 40 pounds or more to hold a heavy wetsuit or drysuit and AL-80 down for the dive.

Weight and buoyancy are two very different concepts and both are important in this decision. Study and ask if they do not become clear to you.

Here is an old post that walks through a real comparison.
http://www.scubaboard.com/showpost.php?p=1191538&postcount=16

Competition is lowering the prices of HP steel cylinders. The 80s in particular can be had for about $200 complete with boot and valve.

Pete

 

[Skeeter1097]

Ask yoursalf two questins. How much air do you use and how oftin are you going to dive. Cost is a big question as well. alumin or steel $125 a tank or $300. If you dive compresd air only and your 80 last 40to45 min. That is all you need. If you are going to us nitrox you mite won't to go to 100:s for the rapetive dives. If you drink are like me 100"s are a must.Tomuch tank is a wast too.

 

[spectrum]

Cost is a big question as well. alumin or steel $125 a tank or $300.

That's the big misconception. The HP steel tanks of comparable capacity to the $125. aluminum cylinder only costs $200. If you care to go LP steel you can go from 80 to 130 cubic feet for the same $200 (Current LP Worthington at Scubatoys)

Some LDSs have been gouging HP-80s for $300. or more, that's just plain wrong.

Pete

 

[papps953]

Another consideration is how big (strong) you are. Before you decide to go buy a steel 119, make sure you can lift it, your BCD, and weights (if it's integrated).

Bill B.