Tank Recommenation - Please

[Bob DBF]

I see HP tanks being sold with 200 bar valves. Is that acceptable - or does a 3442 psi / 237 bar tank (eg.Fa

Yes, 200 bar just differentiates it from 300 bar in reference to DIN fittings, rather than the pressure limits of the valve.

 

[-JD-]

The older 3500psi HP tanks with the smaller necks (almost) always use the deeper 300 bar DIN outlets. Nothing wrong with them, I have 12, but you have to use regulators with 300 bar DIN connections. Almost all DIN regs are 300 BAR connection.

The newer 3442 PSI HP have the common, larger 3/4" necks. Using convertable or "pro" valves allows you to use 200 or 300 bar DIN regs or, by screwing in an insert, yoke/A-clamp style regs. Just be sure the burst disks are ones for 3442/3500 psi service pressure - 5000/5250 burst pressure range.

 

[LiteWeight]

My dive buddy is a petite lady in very good shape, so I always end up being the limiting factor when it comes to air. Like most, we are using standard AL80 tanks filled to 3,000 psi.

Now I want to invest in new tanks that will equalize the time we can spend below - and I need some input.

1. The new tanks should not be bigger or heavier than the AL80.
2. The new tank should ideally provide 20% more air than the standard AL80 at 3,000 psi.

A high capacity AL80 filled to 3,300 could of course be an alternative, but not fully meet the +20% citeria.

Steel seems to be the better choice. A 100 cu.ft tank appears to be almost identical to the AL80 when it comes to size, but would that provide the extra capacity I need?

And then the question about LP vs. HP. Some have expressed concerns about the extra strain of HP on the first stage. Is that a real concern?

Steel tanks galvanized, not stainless, I understand. What about rust? What about hot-dip vs. spray/epoxy?

And there is the question about the valve. Any choices there?

Any other issues I should consider? (I am aware of the buoyancy difference.)

Your education effort will be greatly appreciated!

Well your profile doesn't even mention what country you're in, sorry if I assume you're from the US as I am (since you've mentioned Imperial pressure units) Like others have said, X7-100's are awesome, and if she has an 80 you'll keep up just fine.

However, the short little 80's don't fit in most tank racks. This can be aggravating as hell on some smaller boats. Please don't do this to a charter captain.

Solution - buy 4 X7-100's. If she's like my gf, she can make 2 dives on 1 fill.