Pressurized CO2

rrkss

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May 7, 2006
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I finally got my 5 lb aluminum cylinder, a regulator, some 3/8 internal diameter tubing, a 1/4 to 1/8 needle valve and some hose clamps. I set everything up, set the regulator to 9 psi and now need help with the bubble flow rate. I set it to about 1 bubble every 2 seconds for my 29 gallon tank. How would I go about fine tuning this thing without causing a massive algae problem due to unstable CO2. I just got fed up with BBA algae constantly growing on my Amazon Swordplant so I gave in to a pressurized system from my old DIY system.
 

VaughnH

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Re: Pressurized CO2

I suggest first raising the regulated pressure to about 20 psi instead of 9. Then crack the needle valve until you get around one bubble per second. Watch it off and on until you know it remains constant. Then try sutting off the solenoid, waiting a minute or so and opening it again to see if the bubble rate resumes at the same setting. If all of that is ok, start checking the fish to see if they act normal and don't cluster at the top of the tank, lose color, or otherwise look distressed. Then raise the bubble rate a little each day until you finally see some distress in the fish - don't ever raise it and leave it unwatched for a day! When you see some distress, back off a bit on the bubble rate and make sure the fish act normal again. That is the highest, and therefore the best bubble rate for that tank, with that method of diffusing. Remember the bubble rate, remember the pH and KH and use those numbers to control the CO2 to a constant rate. Let the solenoid shut off the CO2 at night to give the fish a break, and turn it back on for the lighted period.

Rather than worry about what the tables say your ppm of CO2 is now, just treat that number as a dimensionless indication of what you will now use as your CO2 flow rate. So, if your KH changes, you can still go back to the same CO2 rate using the tables. You just wont know what that true rate is.
 

rrkss

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May 7, 2006
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Re: Pressurized CO2

Where would I find a solenoid since I would love to automate turning on and off the gas. Right now I have a manual ball valve to shut the CO2 off at night and on in the morning. I'll start with 1 bubble per second and see what that does. On the weekend I'll crank up the CO2 and watch the fish.
 

rrkss

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Re: Pressurized CO2

VaughnH said:
I suggest first raising the regulated pressure to about 20 psi instead of 9.

This makes fine tuning my bubble rate much more difficult is there some specific reason to why I need higher pressure? One more question, my tank reads 750 psi. Is this about normal since I expected it to be 1000+ PSI.
 

VaughnH

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Re: Pressurized CO2

rrkss said:
Where would I find a solenoid since I would love to automate turning on and off the gas. Right now I have a manual ball valve to shut the CO2 off at night and on in the morning. I'll start with 1 bubble per second and see what that does. On the weekend I'll crank up the CO2 and watch the fish.
Here is where I bought one: http://www.rexgrigg.com/sale.html and it is a good one. (Scroll to the bottom of the page to see it. And, ignore the crude language!)
 

VaughnH

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Re: Pressurized CO2

rrkss said:
This makes fine tuning my bubble rate much more difficult is there some specific reason to why I need higher pressure? One more question, my tank reads 750 psi. Is this about normal since I expected it to be 1000+ PSI.
CO2 tank pressure will be around 800 psi at 70 degrees F. The pressure will vary with temperature. When you start to run out of CO2, the liquid in the tank will be gone and the pressure will start to drop - that's the time to refill the tank.

I found that I needed about 25 psi from the regulator to maintain a steady bubble rate, when I used a ceramic disc diffuser. The diffuser and the check valve both take some pressure to allow CO2 to flow, so if the regulated pressure is too low the bubble rate tends to surge and drop, surge and drop, and sometimes just stop. With the setup you have a lower pressure might be ok.
 

Tom Barr

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Jan 23, 2005
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Re: Pressurized CO2

If Rex did not have the crude language, I would not respect him. :D

The best set up would be a decent solenoid, Victor regulator, Swagelok needle valve(2 per tank) ADA Ruby check valve bubble counter(these are really cool), ADA diffuser and a reactor.

I'm playing with a reactor and a misting disc.

You can rise the KH as suggested, more water changes. 5 gal vs 10-15 is not much on the tank.

Blast the CO2 out into the sword.

You'll need to pull the sword out in about 3 months because it will outgrow the tank.

Regards,
Tom Barr
 

VaughnH

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Re: Pressurized CO2

You have to email Rex to order the solenoid valve: [email protected]
The one you referenced is a Milwaukee valve. My regulator is a Milwaukee all in one unit with that Milwaukee valve on it. The valve failed to close after 2 months in use, which is why I purchased one from Rex. The one from Rex is ruggedly made, looks like it would be reliable, and has been for over a month now. And, it is cheaper than the Milwaukee one you referenced.
 

TexasRock

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May 31, 2006
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Re: Pressurized CO2

Rex only uses quality parts on his regulators/solenoids... when I buy another one, I'm definately going through him!

Keith