Hey again!

[Rapid Rat]

I’m trying to get on to the classifieds. I’m looking for a pony tank or two because Of the weight considering all of g
the gear I carry. Can anyone explain to me why some tanks can fill around 3400 while my traditional 80ft are filled to to the mid 2000 range? Being new at this I realize this post is in the wrong location. I apologize to the admins
thanks!

 

[Zef]

I’m trying to get on to the classifieds. I’m looking for a pony tank or two because Of the weight considering all of g
the gear I carry. Can anyone explain to me why some tanks can fill around 3400 while my traditional 80ft are filled to to the mid 2000 range? Being new at this I realize this post is in the wrong location. I apologize to the admins
thanks!

Some tanks have a higher working pressure rating than others.

Note that your tank is 80cuft (cubic feet) not 80ft.

Without a visual of the markings stamped above the shoulder of your tank, your tank either:
1. has working pressure rating in the mid 2000psi range

2. your tank is being filled to 3000psi, but the tank heats up when filled so its possible when it cools the pressure drops to mid 2000psi range.

3. your shop is not filling your tank to the rated working pressure.

Post some pictures of the info stamped into your tank so we have more info to go on.

To get to the "Classified" section: follow this link to the Diving Gear forum and you will see under each gear type sub-forum there is a link toa classifieds sub-forum for that type of gear.

-Z

 

[Rapid Rat]

thanks for the reply. I want the best of both worlds I guess. My 80’s get pretty heavy on my trips down river But the dive time will be less. I’m wondering how much a 50cuft tank will cost me vs having one that is used and shipping. I will keep an eye on the classifieds

 

[Zef]

thanks for the reply. I want the best of both worlds I guess. My 80’s get pretty heavy on my trips down river But the dive time will be less. I’m wondering how much a 50cuft tank will cost me vs having one that is used and shipping. I will keep an eye on the classifieds

I recently bought a used aluminum 80, It was filled, had a new vis inspection sticker, and 2 years left before it needs to be hydroed. I got an OK deal but had I checked Dive Gear Express, Dive Right In Scuba, etc. I could have gotten a brand new tank for +/- $70 more.

If you are looking to buy an aluminum tank, then check new prices as I think that is better route. For steel tanks, used tend to be less expensive enough compared to new that good deals can probably be found if patient enough.

-Z

 

[TMHeimer]

I found that if I leave my tanks at the shop for a fill and come back later they have more air than if I sit there waiting for them. Has to do with the tank not cooling down I think.

 

[loosenit2]

Tanks are made of two materials, Aluminum and Steel. Almost all Aluminum Tanks are rated to 3000psi. Steel tanks come in two varieties, Low Pressure and High Pressure. LP tanks are rated to 2400 but when they are hydro tested if they meet certain specifications they can have a + stamp, which allows them to be overfilled by 10%, so they end up with a rating of 2640. High Pressure Steel tanks are service rated to 3442 psi. Link below from DGX has very comprehensive run down of things to consider.

How to Select a SCUBA Tank | Dive Gear Express®

How to Select a SCUBA Tank How to choose the best SCUBA tank for specific diving needs and styles of diving.

www.divegearexpress.com

I would also encourage you to look at buoyancy characteristics of tanks. "Heavy" is relative. Some tanks may be "heavier" on the surface but less negatively buoyant when underwater because of the volume of the tanks.. remember archenemies principle. So higher volume tanks with lower pressure tend to be less negatively buoyant. For example a Low Pressure Steel 85 tank is 7" in diameter, and ~26 inches tall, has a service pressure of 2400 and is negatively buoyant by -2.43 lbs when full and positively buoyant by 1.24 lbs when empty. Compared to a Steel HP 100 tank which is 7.25" in diamater and 25.3" tall and has a service pressure of 3442 which is negatively buyoyant by 8.4lbs when full and remains negatively buoyant by -0.6 lbs when empty. The two tanks are very similar in size but have very different buoyancy characteristics and different air capacities.

The DGX website generally lists this data for their tanks so you can compare relatively easily.

 

[TMurrr]

thanks for the reply. I want the best of both worlds I guess. My 80’s get pretty heavy on my trips down river But the dive time will be less. I’m wondering how much a 50cuft tank will cost me vs having one that is used and shipping. I will keep an eye on the classifieds

Where are you located? I have two 50cu feet tanks for sale

For Sale - (2) Scuba tanks - AL50's

(2) Luxfer aluminum 50 scuba tanks Current hydro / visual (Feb 2022) HOG "edge" Tank Valve Pro Style (DIN/yoke) 232 Bar Left/Right Hand matching set Great tanks, they're just too small. Would double up really well too $100 each $180 for the pair OBO Located in Fort Lauderdale, FL - 33304

scubaboard.com

 

[Rapid Rat]

Thanks for your replies,,and the science behind them…I have some reading to do!
When I used the term heavy, I should have used cumbersome as it was in regards to lugging them behind me in a float in the shallow parts when they’re not being used, and toting them back to the Jeep!