Why the cap on tanks?

[CephBirk]

Is there any particular reason people keep the little rubber caps on their tanks? Is this just a convenience for dive shops as a way to indicate whether a tank is full or not that just spills over to divers who own their own tanks? Especially for a yolk valve, I don't see much harm in letting it sit uncovered. Maybe crack the valve a moment to blow some dust off after long storage, but other than that... am I missing something?

 

[nadwidny]

Some shops and people use them to tell empties from fulls Some people use them because they saw them on the tanks during their course and figured that's what to do. Some people use them because they look pretty. I suppose there are many other reasons.

 

[Bob DBF]

There are worse things than dust that could get into the valve. Also it keeps the o-ring in place.


Bob

 

[Marie13]

Especially for a yolk valve. am I missing something?

It’s to keep the yolk from breaking, unless you prefer scrambled yolks.

 

[PalauDiver]

With yoke valves, there is a possibility of dislodging the o-ring through the course of normal handling, not so much with DIN. There is also the possibility of an impact deforming the seat on older valves. The newer valves with the removable insert don't have the same seat.

 

[mmerriman]

I've had wasps and other critters make nests in the hole when the tanks have been in the garage....

 

[KeithG]

On a LOB in the Caribbean the caps keep salt water spray from collecting on the valve. It is also used to signal that the tank has been refilled by the crew.

 

[Akimbo]

It was pretty common in the early days of the sport for dive shops to cover the O-ring with vinyl tape that included the shop name and contact info. It marked the tank as full, kept crud out, and was advertising. Some divers tanks were covered by these bits of tape like people covered their luggage with "where I've been" decals in the 1900s. I wish I saved some of them so I could frame them for my office.

 

[walkonmars]

I hear your pain. The rubber caps are sometimes a hassle to get on or off because they are a tight fit. I like them to keep spiders from building nests in the valve hole.
I usually hole punch halfway up the back and then cut a slit from bottom to the hole. This allows an easier slip fit on or off the valve. Lately I have so many tanks that I just cut fingers off of disposable nitrile gloves and slip them over the valve. I get 5 covers for every glove. You can also use a slice of an inner tube about 1 or 2 inches long and slip it over the valve. I don't use the covers for impact protection.

 

[Couv]

It was pretty common in the early days of the sport for dive shops to cover the O-ring with vinyl tape that included the shop name and contact info. It marked the tank as full, kept crud out, and was advertising. Some divers tanks were covered by these bits of tape like people covered their luggage with "where I've been" decals in the 1900s. I wish I saved some of them so I could frame them for my office.

I too wish I had my old collection valve tape strips. Due to a few careless divers, the tape strips picked up the moniker "diver's litter" and lost favor giving way to the valve covers.