What bottles do you use for Deco Gas?

[Paulmal]

I am wondering what other are using for multi-bottle deco dives.

I am signed up to take Normoxic Trimix in november but I have been playing with my deco planner for some time and started wondering what divers that are doing these dives use as far as bottles.

[Jim Wyatt]

Aluminum 72's for EAN50, and Aluminum 40's for 100% O2

There was no option for these combinations on the poll.

[WJH]

LP45 Steel for O2. Al80 or Al40 for EAN50, depending on whether the EAN50 is also being used as a travel gas for a long shallow tunnel on the way to the deep part of the dive.

WJH

[outofayr]

Typically AL72s or AL80s for travel gas, 50% and oxygen. Depends on the dive and the logistics, though. Often use an 80 of 50% and an AL40 of 100% or even both in AL40s if a shallower dive, especially on wrecks. For deeper cave dives, depends on the cave. Didn't really have an option in the poll for "all of the above"

[PfcAJ]

Depends on the dive. Depth, bottom time are all at play.

For real short deco times, al40s. Anything else gets a steel72 for oxygen, and al80s for 70, 120, 190.

[Kelly Jessop]

Left off the steel 46,what an awesome tank.

[Jay]

AL 40's for pure O2, Al 80's/72's for the rest. Depends on Deco obligations and the physical configuration of the cave, ie where can I stash a 130 bottle or something.

If you are doing Normoxic you probably only need a 40 for your last deco and something for a 130 bottle.

[SR]

Steel 45 for O2, Al 80 for 50%, AL 80 for Deeper Deco / Stages.
I have use an AL 80 for O2 when I needed extra O2 for contingencies.

[FW]

Depends on the dive. Depth, bottom time are all at play.

For real short deco times, al40s. Anything else gets a steel72 for oxygen, and al80s for 70, 120, 190.

I have to agree with AJ on this. On most short, shallow, deco dives a 40 for O2 is enough. The real answer to the OP's question is to plan the dive then decide on what tanks are needed. If you tend to get light on shallow stops, then steel tanks are a big help.

[PfcAJ]

I find the extra weight at the shallow stops to be nice, especially with a few empty stage/deco bottles clipped off. You're simply less negative with trimix in your backgas. The real benefit is the extra gas though. A delay at depth can really drive up your deco times quickly, and that extra o2 can solve a lot of problems.