Almost ready to buy 2 Faber galvanized LP 85's - sound right?

[sea_otter]

I realize that I wasn't using AL's and comparing to steel tanks, but I think it was a reasonable test of the theory that adding more weight relative to added buoyancy gives a constant result. It didn't seem that way to me.

Did that make sense? I'm not at my clearest tonight...

That makes perfect sense. When you were diving with 22 lbs of weight (yikes!), you had to add a lot of air to your BCD to compensate. Weight may be constant, but air sure isn't. If you ascend even a few feet, that big bubble is going to expand, and it'll pull you up. By contrast, if you're closer to proper weighting, the bubble in your BCD will be smaller, so you'll easily be able to balance out with a simple exhalation.

Get to a point where you're neutral with zero gas in your BCD at 10 ft deep and 500 psi in your tank. That's the appropriate amount of lead, and proper weighting provides better buoyancy control the whole dive through.

As for aluminum vs steel, you should be able to get either one properly weighted, though the aluminum one will likely take an extra block of lead, meaning the whole rig will be slightly heavier on land. This becomes an issue if your exposure protection is so thin that with a steel tank and zero lead, you're still too heavy. Otherwise, either work.

The best thing about AL80s is the price tag. They're cheap. Between the steels, for single tank diving, if the price is the same I'd choose HP100s. I might be swayed to LP85s if the shop could reliably overfill them to 3000, or if I was going doubles (the 85s are a little bit longer and lighter which makes them trim very well as a set). Even if you're not likely to breathe it yourself, more gas is always nice to have.

 

[guruboy]

I realize that I wasn't using AL's and comparing to steel tanks, but I think it was a reasonable test of the theory that adding more weight relative to added buoyancy gives a constant result. It didn't seem that way to me.

Did that make sense? I'm not at my clearest tonight...

You can add air to your BC to increase lift to cancel the extra weight.

However, the issue is that as your depth varies, so does the gas volume. With a lot of extra weight, you will need a lot of extra air. This means your buoyancy will have much larger swings due to changes in depth when compared to a neutral diver with little to no air in his BC.

 

[Bob DBF]

You can add air to your BC to increase lift to cancel the extra weight.

However, the issue is that as your depth varies, so does the gas volume. With a lot of extra weight, you will need a lot of extra air. This means your buoyancy will have much larger swings due to changes in depth when compared to a neutral diver with little to no air in his BC.

The other issue I found, back when I used Al 80's and a jacket, the tank would get butt lite and tend to pull your butt and the jacket shallower, and exerstabate the issue of the BC bubble size increase. Attaching weight to the tank base will help, although you will be butt heavy at the start of the dive. I found a BP/W also will hold it against my back with more control than my jacket did.

My first bought tanks were Al 80's, because of size (that or 72's was the choice) and price. I perfer steel and now the choices of size boggle the mind. The original Al tanks were "bad" alloy and retired, the Al tanks I have now are rarely used as back gas.


Bob

 

[USMC CPL.]

@Johnoly

That's a good one! I've been certified a little over a year. First tank was a 30cft pony I've still got and probably will for a good while. Then I bought 2 AL80s and dove them for a few months. I then bought 2 HP80s and gave my AL80s to my dive buddy on long term loan. He's decided to buy them from me, as he's been converted to tank ownership by the simple convenience (no hassle of returning rented tanks, etc.). I happened to have a spare reg set, exact same as my original, but DIN (original was yoke). Moved everything to the DIN first stage. Loved those HP 80s so much I got 2 more (used). Original yoke first stage is being converted to DIN for pony use, while pony reg is being paired with another one of the same model for side mount for next year.

And heaven knows what tanks I'll end up with for SM when I start my tech stuff in a couple of years. Probably HP100s.

I just picked up a hp 100 from dris. Gonna get it out this weekend and see if I can go zero weight. Looking forward to it.

 

[J322Y]

I found a matched pair of LP85's for sale from a guy on craigslist who makes extra money buying/selling tanks. It's a package deal with all (most?) of what I will need to run them as doubles. His price is $550. Maybe I could get him to throw in a few boots, to boot. That's about what it would cost me buy to new galvanized LP85's with valves and boots from DGX. Thoughts?

From his email:

Current hydro and VIP also tanks have been oxygen cleaned for nitrox use. Bundle offer I would include stainless steel bands, hardware and the isolator for creating dual manifold dot-dot-dot package price $550

 

[divad]

.........

 

[J322Y]

Perhaps I need to slow down a bit......

 

[Caveeagle]

Those are nice tanks And Matt is a good guy!

You should really look into likely places you plan to go diving and see if you can get cave fills there.

If you are into salt water and wrecks, then you will probably be better served with Hp100s

But if your local shop will give good fills and you plan to bring your own tanks down to places like West Palm/ Jupiter, the you might be fine with the 85s.

You should generally have no issue re-selling either.

 

[J322Y]

Those are nice tanks And Matt is a good guy!

You should really look into likely places you plan to go diving and see if you can get cave fills there.

If you are into salt water and wrecks, then you will probably be better served with Hp100s

But if your local shop will give good fills and you plan to bring your own tanks down to places like West Palm/ Jupiter, the you might be fine with the 85s.

You should generally have no issue re-selling either.

Thanks.

I've been renting tanks with over 3000 psi...

Yes, I would bring my tanks to wreck dives already filled I think.

 

[runsongas]

more than i would pay. no vis and the hydro is out in 8 months (looks like 7/13 to me). you would be looking at roughly another 80 dollars to get that done soon and then you would end up with a set of used painted tanks vs new galvanized tanks. could probably get mirrored valves and an isolator for not much more if you emailed dgx directly and asked. a set of used bands can be found for 60ish. i would go like 420 max on that used set. so with some used bands and maybe a bit more to get mirrored valves and the isolator, probably somewhere around 700 to 720 total vs 630 (550 + 80) for hydro/vis on the used set. i can't remember if dgx states their new tanks come o2 clean, but that might be the case also, which makes paying 550 for those fabers even less attractive.