Bad scuba advice you've received

[boulderjohn]

Actually, that fits into the theme of this thread:

About 2 years ago, the shop was very reluctant to fill my buddy's dive-tank that was low, around 200psi. We were able to "convince" them after a little arguing, but it did leave a bad taste in my mouth.

More recently I got my VIP certification. Just to be on good terms with the shop, I explained I had just received my VIP cert, just VIPed the tank, and that's why the tank was empty. The owner was okay with that (as he should be) but then said "you know why we won't fill empty tanks, they should have covered that in your class.." I didn't want to argue and figured, maybe I had missed something, so I didn't really way anything.

I asked my instructor, and he quickly responded that no such requirement exists.

The best I can think of, is that an empty tank may suggest a diver screwing around with their own equipment, and you might want to double-check that the valve is secure or that no debris is in the tank before filling for safety reasons. However, that wasn't anything my instructor mentioned.

Personally, I have a couple more reasons to be annoyed at this dive-shop, but unfortunately I don't really have other practical options for fills at the moment. And I get the vibe that if I did try to argue with him, he might refuse my VIP stickers, and there are probably better hills to die on.

The PADI OW course materials tell you that a low tank can allow water in. They don't explain why a tank with a regulator and more internal pressure than the the surrounding water pressure will allow water in, but they do say it.

 

[boulderjohn]

In some dive plans, technical divers will take stage bottles they carry down to near empty. In one place I have dived frequently, the difficulty of getting local fills created a typical strategy of breathing a stage bottle down before switching to back gas in doubles, thus making it possible to use the same back gas for multiple dives. I can't begin to estimate how many times I have breathed a tank down to near zero under water. I do my own VIPs. I have never seen a drop of water in one of those tanks when I open them up.

 

[Wookie]

On my liveaboard, we often had divers run out of gas.

we always opened the cylinder for a VIP if it was my cylinder.

We did not charge the customer, they were grumpy enough at not being allowed to dive anymore.

There was never any water in the tank. Ever.

 

[SlugLife]

I have never seen a drop of water in one of those tanks when I open them up.

There was never any water in the tank. Ever.

I think to get water in, you'd have to both empty the tank and be very careless. Though I'm wondering if it's even possible.

Lets say you had a scuba tank with 500 psi, submerged, no regulator, opened the valve, shut it, wait, and repeat until it's at 100psi. Actually trying to get water into the tank. Would any water get in the tank? I'm thinking not.

Now that I'm thinking about it, the only place I heard about water getting into tanks being low, is from my open-water class (not a VIP class), and from this dive-shop. So maybe that too is a myth or misunderstanding. Clearly moisture can get into tanks, obviously during fill, or if the valve is ever removed, or empty and condensation, but I'd be curious if it was even possible to get water in there otherwise without emptying the tnak.

 

[Wookie]

I think to get water in, you'd have to both empty the tank and be very careless. Though I'm wondering if it's even possible.

Lets say you had a scuba tank with 500 psi, no regulator, opened the valve, shut it, wait, and repeat until it's at 100psi. Actually trying to get water into the tank. Would any water get in the tank? I'm thinking not.

Now that I'm thinking about it, the only place I heard about water getting into tanks being low, is from my open-water class (not a VIP class), and from this dive-shop. So maybe that too is a myth or misunderstanding. Clearly moisture can get into tanks, obviously during fill, or if the valve is ever removed, or empty and condensation, but I'd be curious if it was even possible to get water in there otherwise without emptying the tnak.

If you empty the tank on descent, as John described, and continue to descend, you will force water in the tank when ambient pressure rises above tank pressure.

It will be a tiny amount of water, as water backwards through a regulator is a tortuous path, and at some point you will snap to and close the valve.

It's pretty hard for a recreational diver to get water in a scuba tank.

 

[SlugLife]

If you empty the tank on descent...

14.7psi is surface pressure. 120ft deep would be about 75psi. So you'd have to get the tank awfully empty, and like you said it would be quite a route for the water.

It wouldn't surprise me if this shop was intentionally selling people VIPs they don't need. For example, I've known a couple shops that were willing to swap valves (including this shop at one point) for free with a fill. However, this shop changed their policy and said they'd only swap valves with a VIP.

 

[BoltSnap]

If a customer brings in a tank that is empty, no air, I'd not fill it until I open it and inspect it. I have had people in the past bring in empty tanks and when inspected found water inside. Some guy not too long ago brought in a tank he was going to buy from guy who teaches scuba without being a certified diver or instructor and found "oil" inside it. Another one had crap inside, it was watery rust at the bottom and sides of the tank. One guy drained his tank while underwater just to feel what it is like to run out of air. When he got back to his truck, he apparently removed the regulator and forgot to turn the valve off. He later dunked his tank in the rinse tank with the valve open. When he brought in for fill, I found lots of water inside the tank.

The moral of the story, there are many unimaginable ways that water would get into the tank if air was drained from the tanks, ways that you wouldn't have thought of them until they happen. Empty tank, no fill until inspected and cleared for filling. I charge for my time to inspect the tank usually (if the customer is a jerk, I am charging him for certain).

 

[mariosx]

I didn't see them in the thread, and I can't be the only one:

• "Bring normal gear. You will enstrangle yourself with this 7 feet hose"
  • LDS operator that refused to let me on his boat (although trained by a known agency), and couldn't show me how I would enstrangle myself when I asked him.
• "No need to bring your light, unless if you want to risk failing for not performing up to standards"
  • All that on a 100 feet dive in a lake where belllow 60 feet there was no visible sunlight. His "light" was like a keychain accesssory, and thankfully I brought my own canister light. It was during my AOW with 2 other students that had nothing to do at 100 feet given their buoyancy. I retrieved one that got lost because he followed a fish and couldn't see the lights. Regarding me failing PPB, he couldn't even hover...
• "It really holds up very well the knife, and you can use it to get away if you get caught during shipwreck penetration." (I reased eyebrows) "Sometimes your hoses and other stuff can get caught in to the structure of the shipwreck, and especially if it's an old one it easier, instead of unscrewing the knife and using it, to directly using the case to bang and break the metal pieces. They break easily in WW2 shipwrecks."
  • Same instructor in the same day, speaking mostly to the other 2 students during the surface interval while showing an old navy knife he had in a case and he was brinking with him and expalining why the case is cylindrical and so heavy.

 

[BoundForElsewhere]

I didn't see them in the thread, and I can't be the only one:

• "Bring normal gear. You will strangle yourself with this 7 feet hose"
  • LDS operator that refused to let me on his boat (although trained by a known agency), and couldn't show me how I would strangle when I asked him.
• "No need to bring your light, unless if you want to risk failing for not performing up to standards"
  • All that on a 100 feet dive in a lake where belllow 60 feet there was no visible sunlight. His "light" was like a fake on from a keychain, and thankfully I brought my canister light. It was during my AOW with 2 other students that had nothing to do at 100 feet given their buoyancy. I retrieved one that got lost because he followed a fish and couldn't see the lights. Regarding me failing PPB, he couldn't even hover.
• "It really holds up very well the knife, and you can use it to get away if you get caught during shipwreck penetration." (I reased eyebrows) "Sometimes your hoses and other stuff can get caught in to the structure of the shipwreck, and especially if it's an old one it easier instead of unscrewing the knife and using it, to directly using the case to bang and break the metal pieces. They break easily in WW2 shipwrecks."
  • Same instructor in the same day, speaking mostly to the other 2 students during the surface interval while showing an old navy knife he had in a case and he was brinking it with him and expalining why the case is cylindrical and so heavy.

More proof we have squashed evolution.

 

[Brian Mullins]

If a customer brings in a tank that is empty, no air, I'd not fill it until I open it and inspect it. I have had people in the past bring in empty tanks and when inspected found water inside. Some guy not too long ago brought in a tank he was going to buy from guy who teaches scuba without being a certified diver or instructor and found "oil" inside it. Another one had crap inside, it was watery rust at the bottom and sides of the tank. One guy drained his tank while underwater just to feel what it is like to run out of air. When he got back to his truck, he apparently removed the regulator and forgot to turn the valve off. He later dunked his tank in the rinse tank with the valve open. When he brought in for fill, I found lots of water inside the tank.

The moral of the story, there are many unimaginable ways that water would get into the tank if air was drained from the tanks, ways that you wouldn't have thought of them until they happen. Empty tank, no fill until inspected and cleared for filling. I charge for my time to inspect the tank usually (if the customer is a jerk, I am charging him for certain).

My wife just retrieved 2 of her tanks that were on loan to a LDS who woul rent/loan them to students. She took them to another LDS for a VIP (it was due) and one tank had salt crystals on the inside, and the other had standing water. We *think* the standing water was from a filter not being changed out at its recommended duty cycle (and filling with water), forcing water into the tank but the salt crystals totally floored us. Needless to say we don't go to that LDS any longer.