Good fills

[bullfrog]

How do you gals and guys go about getting a good fill? My experience has been that I always have 200-300 less than I ask and pay for when I get into the water. Or should I just shut up and count my blessings that I'm able to be diving?

[Gary]

Quick fills are hot fills. They cool off. Some tanks heat up more then others also.

Get them filled in the water an give them a chance to cool off in the fill bin before taking them off the whips. You can fill them hot in a few minutes and get a dive off them but to get a nice cool top off is gonna take much longer.

In the winter (or I've also been to a few shops with chilled/refirerated fill bins) you can sometimes get fills that warm up another 200-300 psi when you get them to the water.

Ask for a certain fill pressure when the tank is cold, bring a pressure gauge (gauges can vary), and measure your tank pressure at the store when the tank is cold (not hot from the filling process)!

If your tank isn’t at the requested cylinder fill pressure; you can ask for a top-up. Note: Not all compressors can fill high pressure tanks to the rated pressure, so ask what pressure the fill station can fill to (if you have high pressure tanks). Also, most Dive Shops / Fill Stations will not overfill tanks (filling past the tanks rated pressure).

Another note: Remember that a 1 degree Fahrenheit temperature change equates to a 5 psi pressure change. So, if you have a temperature change, you will also have a pressure change (less pressure at a colder temperature). Formula: Delta Pressure = Delta Temperature (degrees Fahrenheit) X 5 degrees Fahrenheit

You can always count your blessings!

[amphipod06]

I fill my own or go to the local cave country fill station (so sorry can't give the name here since it would be an endorsement..) of my choice where the fills are in a cold trough and they are usually right on the money or better...

Dive safe,

Celia

[Luxrok]

My instructor taught us to do our gas planning after we got in the water and the tanks settle a little. During the summer you get a shorter dive and in the winter you get a longer dive.

Hans

[Mike]

Any time you fill your tanks there is going to be a difference in what you see on the filler gage & what you actually have when you get in the water.

When your tanks are being filled the gas gets warm from the friction going in & the temperature in the surrounding air in the environment (hot summer days), so they top off at a certain pressure & when you get into the 68 - 70 degree water they cool down, mine always lose 200 - 300 PSI from the station ( at least ) to the water.

You can wait & get them topped off, but the time for them to cool down takes quite awhile ( I doubt you want to wait that long for an extra 200-300 PSI).

Water baths are worthless, they don't buffer explosions or cool tanks down & you wind up with water in your steel tanks which equals rust & accelerates with any oxygen in your tank.

What your experiencing is normal for a fill.
Some shops will over fill your tanks to get a good CAVEFILL, But you will pay the price on down the line with tank expansion in the middle of your tank & loss of integrity of the cylinder.

This being said I do over fill my tanks & know it will lessen the life of my tanks , but I'm also a tank inspector & know what to look out for before the S**t hits the fan.

My 2 centavos,

Mike M

[muzz]

How do you gals and guys go about getting a good fill? My experience has been that I always have 200-300 less than I ask and pay for when I get into the water. Or should I just shut up and count my blessings that I'm able to be diving?

It's simple. Move down here. Or like others have said, check the pressure before you leave the shop.

[skip]

How do you gals and guys go about getting a good fill? My experience has been that I always have 200-300 less than I ask and pay for when I get into the water. Or should I just shut up and count my blessings that I'm able to be diving?

I got tired of the local dive shop filling to 3000 on their gauge and me having 2600 - 2700 at the dive site (hot day, not yet in the water). Dropping them off and pick up later, or waiting around for cooling and top-off was not what I wanted to do either. So i got bigger tanks and LP. Now that 2600 is dang near full and at 125 cf I have more gas than ever....and don't care about the "short" fill anymore!

-skip

[OFG-1]

Do what we did in the '70's. Leave your tanks in a freezer all night, then go and get them filled. Underwater Designers in Jax had a walk in freezer we would put the tanks in. Sure you got a cup and 1/2 of water out of them, but damn it, they were full.

[FW]

Do what we did in the '70's. Leave your tanks in a freezer all night, then go and get them filled. Underwater Designers in Jax had a walk in freezer we would put the tanks in. Sure you got a cup and 1/2 of water out of them, but damn it, they were full.

Do you remember Phil Janca's ice water tank? I got to LR with 4000psi once, just before the burst disks went.