Filling - to submerge or not to submerge, that is the question

[Roughwater]

Hi Guys,

I'm just wondering about the practise of filling tanks and whether or not they should be submerged in water.

I've heard some say that this helps to keep the tank cooler, allowing the fill to be more efficient.

I've heard others say that this is not the case, and that it can make things worse by creating greater stress, having a greater difference of temperature between the outside and the inside of the tanks.

However, I see people practise both still, so was just wondering - is the jury still in session regarding this?

[DMWiz]

Check out this article on the subject.

[comet24]

No cooling benefit for aluminum tanks as they are just too thick to make a difference.

Steel tanks are a different story but I will leave that debate to others.

[No Misses]

There is no benefit to filling in water. Unless you count having your freshly rinsed tank dunked in warm salt water as a benefit. Do you really think that they change that water?

[in_cavediver]

Originally Posted by No Misses

There is no benefit to filling in water. Unless you count having your freshly rinsed tank dunked in warm salt water as a benefit. Do you really think that they change that water?

Unless you dive freshwater.....

My opinion is it doesn't matter so long as the whips/valves are kept clean and dry. If not, its a good way to send moisture into the tank. (course once its hooked up, it doesn't matter)

[WaScubaDude]

Originally Posted by DMWiz

Check out this article on the subject.

Interesting, but bs in the real world. Every fill I have had, in tub or out leaves my tanks warmer than ambient. I think fill ops fill at a certain rate no matter if the tank is in a tub or not. Most if not all fill faster than the recommended rate. Thus physics being physics the tank is cooled faster in water than in air. The difference may be really inconsequential unless the water is cooled in some manner.

As for over fill. Tanks in and out of water are commonly over filled, in fact I request a over fills. Sometimes get um some times don't. But it is far more common to end up with a short fill by the time the tank cools regardless of in water or out fill.

[WaScubaDude]

Also, i am always skepticle when some starts their argument with "set aside logic", blah blah blah.

[cummings66]

Your last two posts make absolutly no sense to me, were there deleted postings you refer to? The link has not even got the words you quoted "set aside logic" in it, nor do any of the other postings I can see.

I also do not see what you're call BS in the article? It seems to be straight forwards and not lying from what I know, nothing to say it's full of BS as you put it.

I'm wondering, did this thread get heated and then postings deleted because something I just do not get your last two postings.

[cummings66]

At any rate, I'll tell you what I was told at my psi cert course. They claim the cylinders being filled in the water are not left there long enough to transfer the heat generated and so for the most part all that happens is you get a fill, risk water being introduced, and got no benefit of the water. The other point they mention is that after a couple fills the water would be too warm to do any good anyhow so that if it is of benefit it would be a very limited benefit that most would not enjoy and they would find as you stated, a warm cylinder being handed back to them with a possible short fill.

I'm in the group of why bother, just fill at a good rate and you won't have problems anyhow. Overfills, don't go there. Why risk it? A cylinder is good for a certain number of hydro test pressure fills, after that it's scrap. Why hasten the scrapping process?

[ektess1]

No water. Waste of time, and you can introduce water into your tank. Get a dry hot fill. When it cool, it will be the correct volume.