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Pressurized CO2...Just thought I'd share.

346K views 413 replies 138 participants last post by  rajdude 
#1 · (Edited)
So, there have been a lot of threads (it seems) lately regarding pressurized CO2. Hopefully, this primer will help alleviate any fears that people have when starting to delve into CO2 as it can be quite intimidating at first. In addition, hopefully this primer will answer some of the most commonly asked questions regarding pressurized CO2.

As this thread will be discussing how to set up a pressurized CO2 system, advantages/disadvantages of using a pressurized setup versus a DIY (yeast) CO2 system will not be discussed in this primer. For more information, please take a look here:

http://www.plantedtank.net/forums/9-general-planted-tank-discussion/107303-newbie-setup.html#5

On to pressurized CO2!

First, when people refer to pressurized CO2, we often read that we will need a "regulator" or a "regulator build." What does this mean exactly? This term is thrown around quite loosely in the aquarium hobby, but a pressurized CO2 system consists of more than just a regulator.

Here are the essential components you will need:

1) A CO2 cylinder
CO2 cylinders come in various sizes. They are often used in paintball guns (usually sold as 20 oz cans). They also come in 2.5, 5, 10 and 20 lb sizes (larger sizes such as 50 lb tanks do exist, but they are quite large and bulky, and are not commonly sold outside of specialty applications).

CO2 tanks come with a fitting known as a CGA320 fitting, which is standard in North America. Europe and Asia use different industrial standards. Paintball tanks, however, do not come with this fitting, and come with a pin depression type valve. More on this will follow below.

Many people believe that getting a small, paintball CO2 tank is "cheaper", however, this is not usually the case. Regulators (see below) often come with CGA320 fittings (or can be adapted to such). However, as paintball tanks do not contain this CGA320 fitting, normal regulators cannot be used, and you must purchase either a special regulator with the required fitting, or look around for a paintball tank to CGA320 adapter (often, quite difficult to find). In addition, refill costs for CO2 tanks are generally not much different. The refill cost for (say) a 5 lb tank and 10 lb tank may only be a few dollars different. For example, I can get my 10 lb tank refilled for $17.50, while a 20 oz paintball tank may cost $5 to refill. This means that the cost per pound of gas is more for a smaller tank. In addition, the larger the CO2 tank, the longer you can go without refilling the tank, etc. It can be quite a hassle to drive out and refill the tank, depending on where you live. The general piece of advice is to get the largest tank that you can afford and/or is feasible for the space that you have.
 
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#213 · (Edited)
Yea it happened to me on my 20gal. I didn't have the NV set right or I thought it was set right but 5HRS later everything dead 15-20 neon tetras, 2 glow tetras, 2 Siamese algae eaters, my 3 Cory's were weak and so was my yoyo loach. A lot of death that morning. When it's to high (CO2) you will see the fish gasp for air at the top of the water in the tank then after they will be floating upside down. If it ever happens to anyone n u catch it in time put an air stone connected to a air pump and get as much air as u can in the tank and either shut the CO2 off or turn it down.
 
#214 ·
Sorry to hear about your losses :-(
My fish are doing pretty good tho. No gasping, or weird behavior. So I think my CO2 isn't yet at killing levels.
However, my bobble counter is going crazy with too many bobbles to count. And the inline diffuser fills tank with lots of mini bobbles.
I am wondering if it's normal. Maybe for 80 gal tank it is how much is needed.
What you think?
 
#215 ·
Yea I don't even run a bubble counter on my custom 70 just have 2 drop checkers an they stay light green with no problem from the fish n my plants are over grown right now I cant seem to get rid of my duckweed and ricca that's floating everywhere ill toss a bunch and its back in a week lol u should see the apongeton I just took out 24" long with a ton of plantlets.
 
#216 ·
Yeah, mine also grows huge and very fast too.

So I almost doubled the CO2 dose today. All fish still doing fine. Shrimps went close to the surface tho - that maybe a sign.
Will give it a week and see what happens.
Whole tank looks like filled with soda water - don't really like that much bobbles - maybe I should ditch the inline diffuser.
The idea was it would be more efficient and better dissolve CO2 - therefore I would need pump in less. But it doesn't seem to make much difference :-(
 
#222 ·
No, but at some point, the CO2 you are injecting will just be wasted.

So I recently set up a paintball CO2 with an ASA valve and a Watts LFA 41 needle valve...does anyone know why I'm unable to control the bubble flow with the needle valve? I've already killed 3 fish...possibly due to the fact that it either gives me like 10 bubbles per second or no bubbles per second...
The needle valve (really, more of a flow valve) will not help control the CO2 flow rate to the level that we require in our hobby. I would suggest you get a needle/metering valve that is capable of reducing the flow to much lower levels.
 
#220 ·
So I recently set up a paintball CO2 with an ASA valve and a Watts LFA 41 needle valve...does anyone know why I'm unable to control the bubble flow with the needle valve? I've already killed 3 fish...possibly due to the fact that it either gives me like 10 bubbles per second or no bubbles per second...
 
#225 ·
I'm having a problem with my vts 253a. I'm not sure why but the blow off valve opened and blasted gas out really loud. My delivery pressure maxed out the smaller gauge so it must have been higher than 30 psi. Is there anything I can do to troubleshoot? Also, how do I close the blowoff valve after it's blown open?

Sent from my SCH-I545 using Tapatalk
 
#226 ·
It sounds like you turned your delivery pressure to the maximum, rather than the minimum. This would cause the pressure release valve (safety valve) to pop open, releasing the gas.

Did you turn the handle counter clockwise as mentioned in my guide? The handle should be very loose. If you open the cylinder at this point, and gas comes out of the pressure release valve, then it means you have a torn diaphragm (which can be expensive to replace).
 
#227 ·
I followed the guide exactly. I turned the handle country clockwise until it was a few rotations from falling out. I tested while it was not hooked up to my tank and the delivery pressure was around 15psi but when I hooked it up it went higher.

Yes, as soon as I open up the cylinder gas does come out of the relief valve. If I replace the diaghram how do I know the new one won't break again?

Sent from my SCH-I545 using Tapatalk
 
#228 ·
I followed the guide exactly. I turned the handle country clockwise until it was a few rotations from falling out. I tested while it was not hooked up to my tank and the delivery pressure was around 15psi but when I hooked it up it went higher.
I assume you meant counter clockwise.

How did you test the regulator when it was not hooked up to your CO2 cylinder? If it was already indicating 15 PSI, then it may be indicative that the gauge was broken from the start.

Yes, as soon as I open up the cylinder gas does come out of the relief valve. If I replace the diaghram how do I know the new one won't break again?

Sent from my SCH-I545 using Tapatalk
Unless you try to exceed the maximum pressure that the diaphragm can withstand, it should hold. In general, that is what the safety release valve is for.
 
#230 ·
So with the solenoid shut, you first turned the regulator knob counter clockwise. Then you opened the CO2 cylinder valve.

The high pressure gauge should read ~800-1000 PSI (if it is newly filled, you should give it ~24 hours to equilibriate to room temperature before using it).

Then you turned the regulator knob clockwise slowly, and the low pressure gauge immediately jumped past 30 PSI? Or did the gauge read more than 30 PSI as soon as you opened the cylinder valve?

Need to know exactly how you tested it (for 3 hours) to be able to troubleshoot.
 
#231 ·
I had the gas in my house for a few days and once I finished building everything I assembled all the parts. The high pressure gauge read about 790. I tested briefly with the solenoid shut and then tested for about 10 minutes with the solenoid open and the bubbles going at about 2 bps. Then I hooked it up to my tank to see how it worked in line with the diffuser. It read over 30 psi once hooked up to the sump return. I had already turned the Low Pressure adjusting screw very loose before I set it all up. The low pressure gauge immediately went past 30 psi (could this be water pressure pushing back?). I had this hooked up to my diffuser for 3 hours or so, then suddenly it went.

IIRC with nothing attached the low pressure gauge was reading over 15psi. Looking at a pic with the system running to free air(not to the tank) its somewhere around 21-23 psi.
 
#232 ·
With nothing attached, and the low pressure gauge reading over 15 PSI, this indicates that you have a defective low pressure gauge.

From the sounds of it, it is most likely a torn diaphragm.

Can you do the following?

1) Shut off CO2 cylinder
2) Attach regulator and downstream post body parts (needle valve, solenoid, etc) to the CO2 cylinder
3) Ensure that the regulator knob is fully backed off (loose, turn counter clockwise to achieve this)
4) Read the low pressure gauge (if it is 15 PSI as you mentioned, then the gauge is indeed broken).
5) Ensure that the solenoid is unplugged (i.e. so gas will not flow).
6) Slowly, open the CO2 cylinder main valve.
7) Read the high pressure gauge pressure.
8) Does gas come gushing out of the pressure release valve? If so, shut off the main CO2 cylinder valve.

If 8) is true, then you have a torn diaphragm, or your CO2 cylinder has been overfilled (unlikely, since you said the high pressure gauge read 790, unless it is also broken - what does it read when the regulator is off the CO2 cylinder?)
 
#233 ·
Gas comes gushing out as soon as I open the valve. I tested this a few times. The HP gauge reads 0 when it's off the cylinder. I'm not in front of the assembly now since I just had to head into work. I'm going to be back there at 6pm EST-ish. In the meantime I think I might purchase a new low pressure gauge and diaphragm from weldingsupply.com. Based on the product documentation hereVictor VTS 250 Series Regulators I think I need part 0731-0015 and 1424-0009.

They don't seem overly expensive. Does that look right to you?
 
#234 ·
It does indeed sound like the diaphragm is ruptured then.

In terms of pricing, the parts themselves are generally quite cheap, as you have found, but the tools and technical know-how to replace them are usually not readily available; you may have some luck at a local welding supply store (they may be able to help you open it up, etc) - however you want to be sure you know what you are doing, because if the diaphragm is seated incorrectly, you could have a potentially dangerous piece of equipment.
 
#235 ·
I'm going to give it a go. I think I can get it all put together to the proper specifications. I work for a manufacturing company so I'm reasonably sure I can get the proper tools etc to assemble it correctly. Thank you SOOO much for the help Darkblade48. You really helped me out.
 
#237 ·
OK the parts are backordered so it's going to be roughly 10 days until they even ship. In the meantime I have another question. When I did the leak test with soapy water there was air escaping from the threading on the relief valve. I pipe doped it and reseated it. After that there was no leak. Would that be an indication that something else was wrong?
 
#239 ·
Did you discover the leak before or after you did the testing?

If you fixed the leaking release valve before you did the testing I asked you to do, then it is a ruptured diaphragm.

If you found the leak afterwards, then please repeat the testing.

Thanks for the good CO2 FAQ
You're welcome :)
 
#240 ·
OK so I finally received the parts I ordered. I opened up the regulator and I visually inspected the low pressure diaphragm. It was not torn. I replaced it anyway since new parts can't hurt. I also replaced the low pressure gauge.

I think it might be the release valve itself, but I'm not sure how to troubleshoot that. Any thoughts?

OR did you mean the high pressure diaphragm? If so that would make sense.

Sent from my SCH-I545 using Tapatalk
 
#241 ·
From what I understand, your regulator knob is loose and turned all the way counterclockwise when you attach the regulator to your CO2 cylinder.

Upon opening the CO2 cylinder valve, gas immediately start coming out of your pressure release valve.

This indicates a possible diaphragm rupture (high pressure side).

The low pressure diaphragm is not even in use yet, since you said that the regulator knob is turned all the way counterclockwise and loose (this means gas from the first stage has not even entered the second stage yet).
 
#242 ·
OK so I bought the wrong parts. I need the high pressure diaphragm. If the high pressure diaphragm is working properly, there should be be zero gas coming from the relief valve or the relief valve socket correct? Do you know if the high pressure diaphragm assembly uses a different size diaphragm than the low pressure one? I was able to buy the low pressure diaphragm solo, but it looks like the high pressure one only comes as an assembly.
 
#248 ·
Thank you so much, for a newbie to pressurized C02 this was invaluable to me. I have used DIY years ago and resuming my interest in planted aquariums again. This time I didn't skimp on my tank.
 
#255 ·
Just say me how to fit it and when to open the nozzle ??
I'm still not sure what you are asking.

Just put the regulator onto the CO2 cylinder (you can see the threaded part). Then follow the instructions as I have outlined in this thread.
 
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