# When is it time to refill CO2?



## supersmirky (Oct 22, 2008)

I have a 10 lb tank and the pressure is reading a little under 800 psi but not in the red where it says to order more CO2. When is everyone changing their Co2?


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## Veloth (Jun 25, 2008)

I will change mine when it runs out. I'm thinking about getting another tank so I can just swap it out when it's empty.


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## vancat (Nov 5, 2004)

You don't want "end of tank dump"!
When the needle drops below the 800 start making plans to refill- you'll have a couple weeks.

I don't think Dave Gomberg will mind me quoting him...

"As you use the CO2 in your cylinder, it gets lighter and lighter. When you have used about 80-90% of the gas, the pressure starts to drop from the 800psi or so it had when it was just filled. If you keep drawing gas, it will drop to zero eventually. But you don't want to do that, because at about 500psi or so, the regulator becomes unstable.
When the critical pressure is reached, the regulator will dump the entire remaining contents of the tank into whatever comes after the regulator. When this happens, the pressure on the output side of the regulator will rise dramatically. You can try to protect your aquarium by putting a pressure relief valve set at 20 psi or so on the output side of the regulator so this excess gas will just be vented into the room that contains the cylinder. If you were dumb like I was the first time, all the gas will be pushed into your tank. If you have a glass lid on it like I did, the "air" space over the tank will be monopolized by CO2, to the exclusion of oxygen. After a few hours your fish will die of anoxia.

Replace the tank when the pressure starts to drop, just like the gauge says. There is another reason to replace the CO2 cylinder when the pressure starts to drop. Catastrophic regulator failure described above frequently damages the regulator itself, often by making a hole in the diaphragm. This damage is not covered under warranty, it is your responsibility to ensure the CO2 cylinder is replaced before regulator failure occurs.

You can tell the tank is running out in a couple of ways. First, keep an eye on the high pressure gauge. When it begins to move off the 800psi or so it had originally, it is time to replace it. Another tool is to weigh the tank. The tare (empty) weight is usually stamped into the tank near the shoulder (ask your CO2 supplier to show you). Add two pounds for the gauge and the rest is CO2. When 80% of the CO2 is gone, it is time to be careful.

Of course the best thing is just to replace the tank. But if you can't do that for a few days, one strategy is to shut off the master valve. One filling of the high pressure side of the regulator will last for several hours (see the section on leak testing). That way, if the tank starts to seriously empty the regulator will not dump the whole thing."


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## supersmirky (Oct 22, 2008)

good info. Thanks...I definitely need to change my tank then. I found that my HOme Depot exhchanges the 10 lb tanks for only $13 so, I will be there tonight! Thanks again guys!


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## vancat (Nov 5, 2004)

Glad to help.
penny


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## Seattle_Aquarist (Mar 7, 2008)

Hi supersmirky,

I agree with vancat, avoid "end of tank dump". I change as soon as the pressure drops below 800 PSI. At that point the liquid CO2 has all been converted to gas and the pressure drops quickly (I run two tanks off of my tank).


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## Squawkbert (Jan 3, 2007)

^ agreed, as soon as you see that the tank pressure needle is no longer "parked", it's time to change.

All I really wanted to add is that the whole end of tank dump thing can be greatly ameliorated by using a 2 stage regulator.


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## supersmirky (Oct 22, 2008)

Squawkbert; said:


> ameliorated


And yes, I did have to go look up this word!! lol....i knew what the intention was in the sentence but never heard this word before. :loco:


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## vancat (Nov 5, 2004)

ooooh! I love learning new words.
ameliorate |əˈmēlyəˌrāt; əˈmēlēə-|
verb [ trans. ]
make (something bad or unsatisfactory) better : the reform did much to ameliorate living standards.


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## Manwithnofish (Mar 12, 2008)

Squawkbert said:


> ^ agreed, as soon as you see that the tank pressure needle is no longer "parked", it's time to change.
> 
> All I really wanted to add is that the whole end of tank dump thing can be greatly ameliorated by using a 2 stage regulator.


At what price? Is this the same choice I had when the popsicle truck came by ...orange or purple?


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## CaptainNemo (Jul 11, 2008)

I run a low-pressure regulator after my main regulator as well. Drop it to 50 psi with the main, 10 psi or so with the low-pressure. I've never experienced end-of-tank dump. I don't even know I'm out until my drop checker doesn't change.

Only other possibility is that I use a 50# cylinder, don't know if that would matter. I've never used a 10#.


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## supersmirky (Oct 22, 2008)

Okay...so I exchanged my tank however the pressure valve shows 650 which is a lot less than what my previous tank shown. Does this mean they might have exchanged for a tank that wasn't really full or does the pressure not really mean much?


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## orlando (Feb 14, 2007)

Wait for it to reach ambient room temperature. It should go up.

-O


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## supersmirky (Oct 22, 2008)

Oh!!! Okay, thanks Orlando.


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## SpeedEuphoria (Jul 9, 2008)

http://www.plantedtank.net/forums/p...re-relation-room-temperatures.html#post287886


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## supersmirky (Oct 22, 2008)

Good link.


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## Left C (Jun 14, 2005)

You can use a good dual stage CO2 regulator and run the CO2 cylinder until it is empty without "end of tank dump."

http://www.plantedtank.net/forums/equipment/72328-victor-co2-regulator-pimp-club-5.html#post712820

http://www.plantedtank.net/forums/equipment/72328-victor-co2-regulator-pimp-club-2.html#post704141


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## inkslinger (Jan 1, 2005)

Where I get mine fill they put it on a scale and weight it when it was empty and when it got filled wrote down the weight under the tank so all i have to do is put it on a scale and check it


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## Squawkbert (Jan 3, 2007)

If you're shopping for a new regulator, single or dual stage will make a difference in price - not huge, but there will be a difference.

If you're perusing the used offerings on ebay, it's nearly a orange/purple popsicle type distinction.

There are good 2 stage regulators on ebay for cheap on any day of the week, the tricks are to know what brands are good, and to buy from someone who knows a good regulator from one that is dead.

TPT included LINK details some Victor models, prices, what some units were stolen for on ebay etc. etc.


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## Manwithnofish (Mar 12, 2008)

Here, read this.. http://www.aquaticplantcentral.com/forumapc/equipment/38577-just-wiped-out-tank-fish-6.html

Victor regulator and ideal needle valves ...ROCK.


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## Left C (Jun 14, 2005)

Here is an excellent Victor VTS-450D dual stage Oxygen regulator for $65. You can convert it to CO2 use by just swapping the oxygen fitting for a CGA-320 nut and fitting for a few dollars. This is like the king of dual stage regulators. But, you can't convert it back to an oxygen regulator because you want oxygen purity.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWAX:IT&item=200284795080

Here is what Captain Hooked said about his: From: http://www.plantedtank.net/forums/equipment/72328-victor-co2-regulator-pimp-club-7.html#post715229


Captain Hooked said:


> I received the parts and finally set up my 450 series the other day, and all I can say to those who are debating buying a Victor is:
> 
> _You cannot fully appreciate the quality of a Victor until you hold one in your hand and hook it up for use. They are built like nothing else. The expression "gorilla with silk gloves" comes to mind. Are they overkill for aquarium use? Yes, but that isn't the point when you can score a used Victor for about the price of a new (inferior) regulator. Buy them cheap and never look back._
> 
> ...


From: http://www.plantedtank.net/forums/equipment/72328-victor-co2-regulator-pimp-club-13.html#post731301


Captain Hooked said:


> Here's my 450D reg (which is getting a new cga' inlet) next to an Aqua Medic. I think the 'Medic has gauge envy....:redface:


From: http://www.plantedtank.net/forums/equipment/72328-victor-co2-regulator-pimp-club-13.html#post731322


bsmith782 said:


> Wow I had no idea that regular regulators were that tiny.


From: http://www.plantedtank.net/forums/equipment/72328-victor-co2-regulator-pimp-club-13.html#post731395


fordtrannyman said:


> Your right! I did get a kick out of seein' that. LMAO
> That Aqua Medic is just a toy!


From: http://www.plantedtank.net/forums/equipment/72328-victor-co2-regulator-pimp-club-14.html#post731610


Captain Hooked said:


> I laughed the whole time I was taking those pics- could barely hold the camera steady.
> 
> All joking aside, the "little guy" has its place. I'm about to use it on a small alum cylinder for a small tank in a small cabinet- one which the Victor could never fit into. Also, the Victor would topple such a small, lightweight cylinder.
> 
> I say if you want to buy a regulator that you can get 100% of your investment back out if, one that will squeeze the last bit of CO2 from any cylinder, one that will hold pressure like a vice, and you don't require it to fit into a shoe box- buy a dual stage Victor.


You can check the rest of the thread by following the link that Squawkbert mentioned. From Post #19: http://www.aquaticplantcentral.com/forumapc/equipment/57306-when-time-refill-co2-2.html


Squawkbert said:


> If you're shopping for a new regulator, single or dual stage will make a difference in price - not huge, but there will be a difference.
> 
> If you're perusing the used offerings on ebay, it's nearly a orange/purple popsicle type distinction.
> 
> ...


Here are some pictures of mine. From: http://www.plantedtank.net/forums/equipment/72328-victor-co2-regulator-pimp-club-16.html#post734863


Left C said:


> Hi guys
> 
> Here are some pictures of my Victor regulators.
> 
> ...


This is the start of the thread. http://www.plantedtank.net/forums/equipment/72328-victor-co2-regulator-pimp-club.html


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## supersmirky (Oct 22, 2008)

lots of good info LeftC...thanks


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## Left C (Jun 14, 2005)

Thank you very much, supersmirky.


Victor, Matheson and Concoa make very good dual stage regulators. Ideal and Swagelok make very good metering valves.


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## Naja002 (Nov 15, 2005)

I'm at ~100 psi now. I'll swap the tank out some time this week when it gets between 0-50 psi. EOTD (End Of Tank Dump) is not an issue--just run a low end pressure of 30-35psi. I ran an Azoo at ~45psi. Never had a problem, never an EOTD. I run them dry unless it's just more convevient to swap them out a bit earlier for some reason....

I Fear the EOTD...What do you do to prevent it?


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## orlando (Feb 14, 2007)

A while back I made this video of a customers office tank co2 regulator.
You can see the tank pressure is almost at 0psi and the bubble count is very much steady as can be.
A good Needle valve and regulator will rid your "EOTD" worries for good.
Here is the video.....................


Regards, Orlando


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