Tanks: Proper Filling

I’ve said this before: that air is so important underwater. Today I’m going to show you how to fill a scuba tank – and by you, I mean I’ll show you how a scuba tank ought to be filled. Every dive store is different so I’m not being critical: take this information and watch the next time you take your tank in.

By Alec Peirce

The dive store tank fill station operator ought to check the tank, which he’ll built into the conversation. “Wow. Nice tank. Pretty color. Where’d you get it?” He couldn’t care less. He looks at thousands of tanks. (By the time I finished in the retail business for 47 years, if I never saw a scuba tank for the rest of my life, I’d be a happy person!) What he’s doing is building a conversation while inspecting your tank. He’s looking for any damage, abuse, salt, corrosion and rust; he’s making sure the boot is on and everything is good shape; that the valve isn’t banged around or at a funny angle. He’s ensuring your tank is in good condition.

Next, he’s going to inspect the tank to be sure it’s safe and legal to be filled. (We still get tanks from the ‘60s and there’s no problem with that but they have to be tested and in good condition.) While he’s doing that, he’s also checking the pressure rating. I’ve trained a lot of store staff and have been to hundreds if not thousands of dive stores over the years, and I’ve seen mistakes made. Ninety percent of aluminum 80 tanks are 3000 PSI; most steel tanks are 3442 and some are 3500, and a lot of them are 2400. You’ve got to look. You cannot assume the tank pressure of a standard looking aluminum 80 is 3000.

For a proper air fill, politely clear the area. I know this isn’t necessarily a practice you’ve seen in dive stores but customers should not be close to the fill station. It might sound funny or cruel but dive store employees are paid to face the risk of filling tanks; customers are not and we do not need the aggravation.

The tank fill itself is really straightforward and there’s not a whole lot too it (though every tank fill station is slightly different.) Generally speaking, the operator – after the customer has left – will let a bit of air out to make sure there’s no dirt in the hole, then quickly check the o ring to make sure it’s in good shape. He’ll install the filling whip, close the purge, open the tank valve, and read the pressure in the tank – 800 PSI is good. He’ll set the control panel pressure and simply open the air bank; when it gets to the right pressure, it bleeds off and shuts off the tank.

Then when it’s all done, he opens it up, it bleeds off air, he takes the filler whip off and he’s all done – right? No. When he sets the tank down with the other 27 he has no idea it’s been filled or not. A very important last step is to take a piece of tank fill tape, put it over the opening, and tear off a piece. A lot of people mistakenly think the tape is on there to keep dirt and water out of the hole. It’s not a bad assumption but you’ll find the tape doesn’t often cover the hole. There’s also a responsibility for the diver. When you use the tank, take the tape off – and don’t throw it in the water: put it in your pocket or stick it on tank – and don’t put it back on.

This isn’t the only way to do it, but it is 47 years of experience and certainly the proper way – how it should fit into a conversation at your local dive store and see how well they’re doing. I hope you learned something, and I’ll talk to you again real soon!