# When do you change/refill your Co2 tanks?



## Piscesgirl (Feb 25, 2004)

Do you wait til the 'very end' or do you change it out sometime near the end?


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## trenac (Jul 16, 2004)

I usually wait till the tank is empty, just because I usually don't keep a regular check on the level.


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## JanS (Apr 14, 2004)

My gauges are pretty accurate right down to the end, so I let it go until the flow starts getting sporadic. I've heard people talk about a dump at the end, but I've never experienced that.


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## Piscesgirl (Feb 25, 2004)

You will all laugh, but I was changing them as soon as I saw the level start to change. This time I waited, and it's still been going for three weeks past that!


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## bharada (Apr 17, 2004)

In general, if you're tank pressure guage is reading less than 750psi (at ambient temp over 60°F) you're out of liquid CO2 and running on gas only. Once (if) you notice the drop on pressure it's usually a good idea to get the tank refilled at your earliest convenience as you're probably looking at no more than a few weeks of flow left.


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## bharada (Apr 17, 2004)

Oops. I hope I wasn't breaking into a Moderator's-Only discussion.


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## Piscesgirl (Feb 25, 2004)

LOL Bill, this is an open discussion  What do you mean running on gas only? It's still co2, though, right?


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## John P. (Nov 24, 2004)

Piscesgirl said:


> LOL Bill, this is an open discussion  What do you mean running on gas only? It's still co2, though, right?


Liquified CO2.


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## gnatster (Mar 6, 2004)

A full CO2 tank contains liquid CO2. When the pressure begins to drop thats a good indication that the liquid has all turned to gas and you are almost out. 

Being I have keep a spare full one on hand I wait till it hits 0 and swap.


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## trenac (Jul 16, 2004)

JanS said:


> I've heard people talk about a dump at the end, but I've never experienced that.


That is exactly what happens to mine.


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## Piscesgirl (Feb 25, 2004)

Trena, you mean you get a end of tank dump or do not?


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## trenac (Jul 16, 2004)

Let me clarify... I do get a tank dump, sorry!


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## bharada (Apr 17, 2004)

I had the 10# tank go empty on my last week sometime...not exactly sure when. Luckily, no end-of-tank dump. I only noticed when I was rooting around in the stand and saw the gauge reading 0psi. It didn't sink in that for the previous couple of days the P. gayi wasn't pearling anymore.

Anyway I can be thankful that in this high-light tank (4.8wpg) didn't suffer any algae outbreak due to lack of CO2...but it could be why the Cladophora seemed to have gotten heavier.

I too, keep a spare 5# tank that I swap in until I can get the empties refilled.


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