Newbie question: 60 vs 80 tank

[pasley]

Mo2vation gives good advice. You may well want a lot of gas for latter on particularly if you want to do a lot of real deep stuff or deco diving. Or maybe you don’t want to lug all that weight. IF you are going to buy a dry suit, then more air would be needed for that.

Me, I don’t' want to lugged all that weight and an AL 80 takes me to my NDL on most dives. I normally stay in the under 60 foot range and have well over 1000 PSI in the tank at the end of the dive (dives end based on dive buddies air and some of them are diving 120s). On dives below 60 feet, more often than not my NDL is what calls the dive rather than my air supply.

On a recent dive to 94 feet (2nd to that depth that day) I did not start up until I had 2 minutes of NDL left. Long story short, my ascent was very slow (a good thing) but I also did not get any bottom time back (a bad thing) as I ascended and arrived at 19 feet with a 20 minute stop mandated by my computer. Surfaced with 490 PSI in the tank after a 60:50 minute dive including the 20 minute safety stop. Now it would have been nice to have had a tad bit more air on that particular dive, but I can live with 490 PSI on the surface after the dive.

 

[Aerodog]

If you live in an area with an active scuba community, buy the tank you are most comfortable with TODAY. If you find more air is required as your dive profiles expand, buy a new tank and sell the old one to someone locally. Tanks not abused are one of the easiest scuba items to sell. Personally, I would go with a HP80 like the PST E7-80. Typically 80-90 bucks more than a AL63 but much better resale value. Weight is about the same out of the water but more negative in the water. Size is SMALLER than AL63. Wow, smaller size and less weight on the weight belt! Yes, I love my E7-80, it replaced my AL80 (sold to scottfiji) and put my AL63 in the back of the line. i.e. anytime I thought a 63 was good enough for a shallow beach dive, the E7-80 came out because of its better characteristics wrt the AL63. The AL63 is only used when the E7-80 is empty!

BUT there is nothing more frustrating than having to cut a great dive short because of lack of air!

 

[scubagirl95]

Thanks all for replying. I'm still renting a tank, but will keep all of this in mind when it is time for me to buy one. I'm under 25 dives and my buddy is well over 50. I'm going to stick with the AL63 since the last time we both used AL80s and I had almost 500 psi more than him at the end of the dive

 

[LobstaMan]

Either you have gills or your buddy's got a leak! :10: Welcome to diving.

Lobstaman

 

[BrianM]

The 80 tank holds 33% more breathing gas than the 60 cu. ft. tank.

I am not a math wizard but I think an 80 cu ft tank is 25% larger than a 60. And since it is actually 77 and 63 cu ft, then it is only 21% more gas.

 

[The Kraken]

You are correct, but I was working with the basic nominal volumes for simplicity sake.