Choosing my first tanks

[Jwood]

Very new diver.....only things left to buy are my good cold water wet or dry suit and tanks.
Being the rookie I am....air consumption is not where it should be!
I am still confused as to what the specifics are regarding cu volume and pressure.......does higher psi mean more air or does volume (cu')
I'm not sure if I'll ever evolve to twins......but my local DS
has a special on LP 125's and 135's (both under $400.00)......I am a bigger guy 6'1", 220lbs
So the question is....should I go with big singles and add a substantial pony......or buy 100's and double up some time in the future.
Any help or suggestions would be appreciated.
Thanks

 

[HarleyDiver]

I would rather be the guy offering my spare to my buddy, than the guy looking for air.
Plan as well as you can, but someday that current will shift and you will be left swimming a long upstream leg. Boy won't that extra 25ft taste good.
My only issue with big LP's is some dive boats can't fit them in their racks.

 

[KilgoreTrout]

First off, as a new diver you will probably be in a wetsuit for quite some time. Do the math as far as your weight is concerned. The most important factor is the beginning of a dive on the bottom with a full tank of air.

In my case (6'2" but 170#) I only have 6 pounds that I can ditch (I have a SS backplate). This leaves me a little heavy even after ditching my weight on the bottom which I find great. I wanted to buy a new PST E7-120 but after looking at my weighting situation, I would end up VERY negative even after ditching my weight. So until I get a drysuit, I won't be able to get the tanks I really want.

Of course this is all a moot point if you have a working BC, but we are assuming that it has failed. With a drysuit, you have a redundant bouyancy source so it is not as much of a problem.

As far as volume is concerned... The tank with more cu.ft. will hold more air. A tank with 80cu.ft. @3500 psi will not hold more than air than a 104cu.ft.@2500.

If you are not sure if you will ever evolve into twins, keep your options open! If you can lift a huge single tank, you may not be able to handle the same weight doubled! Your consumption rate will drop over time. Also, you should be gas matching on any difficult dive anyway. (I.e. make sure your buddy has WAY more air than you and consumes less! )

BTW, if you do decide to go for steel, get one of the new PST tanks. You have more options in the same package. They have capacity in the same package because of higher pressure ratings. This without the hassle of getting and keeping a + rating on the tank. If you want LP, just get them filled that way.

Basically, look at your weighting carefully and what load you can actually carry on a pitching/rolling dive boat. The end goal is to be safe AND to have fun.

 

[Jwood]

Thanks!

 

[double125's]

double 125's full with backplate, wings, canister light and other acessories weigh approximatly 150 lbs. The tanks themselves way 125 lbs full and you start the dive negative 20 lbs and will have a 20 lb swing in bouancy from full to empty (these figure are using the oms tanks, pst will be a lot heavier). One other thing, personally I would not suggest buying a pony with the intention of using it on every dive. It is my personal opinion that a pony is for emergencies only.