What tank is right for me?

[NAM001]

1kaJ

I have dove with the al100. I dont use al tanks but on one occasion the boat dropped one of my lp95's overboard with the valve open. They retrieved it from the bottom still splling air but for that dive i used a al100. I did not notice a difference in trim or bouyancy. Generally speaking you have to try each of these tanks because so many issues affect it. the suit you wear, long short heavy lght ride high or low. Its all in the equation. I am 6' 240# and i have been using lp95's as singles for a decade. I was 220 then and they still work fine for me. I also have a lp120 and i dont notice a diffference in the water. Land weight is another matter. Just saying this because you probably have quite a range of tanks that will for for you in the water. You will probably have more a critical issue's with the bcd / wing or the suit you will use. Let me say that i use a BP/W so i don't have inflation issues from jacket pocket areas. It does make a difference. I have lp95's lp85's lp120 and they all dive pretty much the same when it comes to safety stop bouyancy with a single tank rig. My BP/W is a DSS and i have a steel and a kydex and i have the steel weight plates for the steel backplate. I have another brand of al BP. so i can mix and match the plates with the wing to accomodate any tank or water salinity. I have on an occasion worn a belt with 3-4# in it but that is a reasonable amount to dump if needed to swim the rig up controllably.

Make sure you TRY AND THEN BUY with any bouyancy efffecting gear. Tanks plates wings bcd's suits perticularly.

 

[BRT]

There are two separate answers to your question.

The first is that bottom time is dependent upon your SAC rate and multiple factors go into how long and how quickly you go through your air. A smaller person has smaller lung volumes and will typically use less air breath per breath than a larger person. Just plain physics which you can't change. Then you factor in things like trim, efficiency, overall health, etc. I'm assuming your bottom time 80 minutes wasn't at max depth of 120 ft. either. I've never been into double or decompression diving but even without looking at a dive table that would be highly unlikely on an AL 100.

Steel tanks have the advantage that you redistribute the weight from your weight belt (or integrated BC) to the tank. The total weight is the same, except you have moved some of it directly to the tank and not on your belt. So, steel tanks are heavier which you have experienced already. They are also less buoyant when empty so you don't have to add the extra weight for the end of the dive.

The other thing you haven't mentioned is if you're planning on getting high pressure versus low pressure steel tanks. The size of the tank will vary and you can get the same volume of air in a smaller tank by increasing the pressure, hence a high pressure tank. You mentioned the aluminum tanks but they will also have the same volume but at lower pressures so their size will be larger relative to a low pressure steel but the LP steel is going to be larger than a high pressure steel. If you are concerned about the length of the AL tanks you should look into either LP or HP steels.

Total weight is not the same! The aluminum tanks weigh as much or more as the 3442 steels for equivelent air capacity and you can drop 5 or 6 lbs of lead.

 

[Islandheart]

If I could only have one tank it'd be the steel 100.

I have steel 120, steel 100 steel 80 and asst AL.

If I have ow students I use the Steel 80, like the compact size and weighting.

If doing fun stuff or few more dives with AOW folks I go steel 100.

If doing Scientific diving where Max bottom time is needed I go steel 120, but like another said "it's a BIG ONE" and 130's are too much for me. (I'd go dbls vs it)

my .02

 

[Kronek]

on one occasion the boat dropped one of my lp95's overboard with the valve open. They retrieved it from the bottom still splling air

I hope they paid or did the vis for you!