Different Deco Tanks

[adm3745]

I understand that for most deco tanks, people use Al 80's. What are the main reasons for this? Is it closer to neutral buoyancy, cost? Right now i'm looking into buying my O2 bottle for Adv nitrox. I like the AL 40. Why would this selection be better than a Steel 45, or even an Aluminum 45/63? Also why use Al 80's for 70/120ft bottles instead of Steel LP 80s..?

 

[WD8CDH]

If it is a tank you want to pick up and set down while diving, you want it to be close to neutral. If it is hanging from a line, buoyancy doesn't matter much, so most people go by cost.

If it is strapped to your rig and will stay there throughout the dive you need to consider size, capacity, cost and buoyancy.

 

[adm3745]

I only ask because I can get LP 77's pretty cheap but they are quite negative. I would like to buy just one tank for any stage or deco bottle in any given situation. Are Al 80's pretty standard?

For the forseeable future I do not see having to do any stops deeper than 70 ft.
Do people use Al 40's for EAN50 as well or is a larger tank advisable. It sounds a little small.

 

[RJP]

Do people use Al 40's for EAN50 as well or is a larger tank advisable. It sounds a little small.

AL40's for 100% and AL80's for 50% is most common - at least here in NJ.

 

[DA Aquamaster]

I prefer LP 45's as they don't get light and start floating up off the line when near empty, yet are not overly negative, but they are expensive and hard to find. It is hard to go wrong with an AL 40 for O2 and then get an AL 80 or AL72 for 32%, 50% etc or for stage use.

 

[ianr33]

I would like to buy just one tank for any stage or deco bottle in any given situation. Are Al 80's pretty standard?

Let me know how that works out for you

I would get an Al 40 first.Light and small. Holds more than enough O2 for any sane dive. Pretty common to get 2 dives off one fill. (It will last for around 40 minutes at 20 feet)
A 40 would also work filled with 50% for "intro tech" type dives.

If/when the 40 gets too limiting get an Al 80. Can be used for a deco bottle or as a stage bottle.