Do you turn the air off or leave it on after setting up on a tank?

[Celt]

I turn my valves on before getting in the water and turn them off when I get out.

 

[wetb4igetinthewater]

I always have this on my harness. Lets just say somebody could lose a finger or two.
View attachment 748322

Threatening someone with this is usually enough to make the 300 lb MMA fighter to back off.

 

[johndiver999]

depends on how big they are and where you hold it.

 

[Alaskan Scuba Dude]

This is my procedure:
1. Open the valve first to make sure there is gas in it. Turn it off.
2. Set the equipment and check the content again with spg to make sure the tank is full. Turn off the gas.
3. Prior to the dive, open the tank, don the equipment and check everything first before the final buddy check(if I have one).
4. Allow no one to touch my gear after I have put it on.

#4 is an oxymoron.


Either way, you would breathe down your regulator to see if it was closed while watching your SPG before entering the water. Every dive is a trust-me-dive whether you like it or not.

 

[Dark Wolf]

I don't know if that story is true or not. The only thing that I can imagine your instructor might have been concerned about is the 1st stage. Having 3000 psi of internal pressure and a very hot environment might cause more stress on a diaphragm or HP o-rings. Perhaps the diaphragm could deform or weaken?

I have not run into any problems like that with my regs, and I run my steel's at 4k. Maybe it has more to do with yoke vs DIN?

DW

 

[davehicks]

I have not run into any problems like that with my regs, and I run my steel's at 4k. Maybe it has more to do with yoke vs DIN?

DW

I think it's not a real problem.

 

[johndiver999]

If you are concerned about a few psi disconnect reg then. It’s not worth risk to have reg hooked to tank and valve off. Read some of the people on here casually saying they jumped in a few times with valve turned off.

Would it suck if I lost 1000 psi, yes. Would it suck more if I forgot to turn valve on and did a negative entry and proceeded to die? I say yes. You say saving psi is more important.

That’s my thinking, safety above all else, when reg is hooked to tank, valve is fully open.

Most DM on boats here have seen this situation play out, someone about to jump in and DM checks tank and cracks it open for them. Ask any DM who works on boats how many times they’ve had to open peoples valves. It’s because of the reckless thinking that completing the dive and saving psi is above all else.

You just don't get it? I have jumped in with the tank off probably half a dozen times. It is stupidity, carelessness and lack of attention. Leaving the tank on so that it will always be on is ridiculous for the reasons discussed. What if your tank shifts start freeflowing and somebody does you a favor and shuts the valve down? They might not even know or care whose tank it is and not tell you? Then your supposed "benefit" has been eliminated.


Turning the tank off and purging the pressure will make it obvious that that tank is off after the first attempted inhalation - whether it occurs on the boat or in the water.

 

[TMHeimer]

You just don't get it? I have jumped in with the tank off probably half a dozen times. It is stupidity, carelessness and lack of attention. Leaving the tank on so that it will always be on is ridiculous for the reasons discussed. What if your tank shifts start freeflowing and somebody does you a favor and shuts the valve down? They might not even know or care whose tank it is and not tell you? Then your supposed "benefit" has been eliminated.


Turning the tank off and purging the pressure will make it obvious that that tank is off after the first attempted inhalation - whether it occurs on the boat or in the water.

I may have mentioned way back that I used to turn my air on at the house (gear all set up of course) before driving to the site. -- Until that one time when I hit the brakes and something pushed in the 2nd stage purge (what are the chances of that....). I have entered a shore dive maybe 3-4 times years ago forgetting to turn it on, but never jumping off a boat-- that's something I was always VERY careful about.

 

[ScubaJCBS]

Which ever you do before entering the water watch your gauge and take 2-3 good breathes every time. I turn my tanks off after set up.

 

[Belzelbub]

I assemble everything, turn the gas on and check the pressure on the SPG. Then I close the tank valve until almost time to jump in. Then open the valve back up when getting geared up. An instructor told me that if you have an extensive transit in hot weather, leaving the tank valve open could lead to equipment damage? He didn't go into specifics but obviously if the full tank heats up, the pressure will rise. Can someone speak to specifically what equipment may be vulnerable in that situation?

I'd be shocked if there was anything that could be damaged due to that. The same regulators can be used for many different cylinder pressures, including some that are well beyond what the US considers high pressure. Most likely, it's something he heard, and passed along as fact.

My valves are always off until I'm just about ready to dive. BC, tank, regulator are assembled before hand. Tank pressure is turned on and verified just prior to donning the gear. Unless I specifically ask, I will always be the only one to touch my valve. If I were to do a charter, and a helpful crew member touches my valve, I will then be the last to touch my valve.