# question on co2



## shoe997bed263 (Oct 15, 2004)

i have a number of tanks and i want to plant all of them i am going to purchase a co2 system/ bc these systems are so expensive i was wondering if there would be a way to use one system on multiple tanks? is this possible. thanx


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## Pterogho (Feb 8, 2004)

It can be done, by using a pressurized system

It will work at it's best, if you make sure you use the same tube-dimension thru' the entire setup, placed after the reduction-valve. This should give an equal pressure to each outlet. 
You will need a needle-valve for each outlet as well.

The hardest thing will be setting up the system to give the desired amount of CO2 to each tank.
If you add a little to the flow to one tank, you will probably have to calibrate the whole setup to the new setting, as less CO2 will force it's way to the rest of your tanks.


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## Husky_Jim (May 26, 2003)

Pterogho said:


> It can be done, by using a pressurized system
> 
> It will work at it's best, if you make sure you use the same tube-dimension thru' the entire setup, placed after the reduction-valve. This should give an equal pressure to each outlet.
> You will need a needle-valve for each outlet as well.
> ...


It can be done by adding an extra needle valve on each tank's Co2 tube!!!


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## shoe997bed263 (Oct 15, 2004)

one more question. at what point do you need a co2 system? i have 2 watts per gallon in all my tanks if i go up to 3 watts per gallon would i need a co2 system?


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## rbp 4 135 (Mar 2, 2004)

has nothing to do with wpg, just how heavily you are planted.


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## elTwitcho (Jun 22, 2004)

shoe997bed263 said:


> one more question. at what point do you need a co2 system? i have 2 watts per gallon in all my tanks if i go up to 3 watts per gallon would i need a co2 system?
> [snapback]910825[/snapback]​


I'm running 3 wpg myself so I'll let you know. At 3 wpg the plants will likely suck out all available CO2 from the water bringing the ph pretty high towards the end of the day. To prevent this I've set up a powerhead at the surface pointing downwards that comes on when the lights come on. It is my hope that this will provide enough surface agitation to prevent CO2 levels from dropping too far as the water should constantly be absorbing CO2 from the atmosphere. I've brought my test kit over today and am going to do a ph reading in the morning and then at night right before the lights go out. If I see any major change, I'll be adding CO2 immediately.


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## elTwitcho (Jun 22, 2004)

Scratch that, I just did a water test right now since I have my high range ph test lying around, lights have been off for a few hours but the test read between 7.4 and 7.8 . I'm going to be injecting CO2 as of tommorow because at least in my setup, the 3 wpg produced a pretty big increase in ph. Thankfully the fish is ok, looks healthy as can be to be honest. The lights aren't going on tommorow until I get CO2 worked out though.


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## shoe997bed263 (Oct 15, 2004)

my ph has been constant at 2 wpg. i have not had a problem with it. thank god


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## Mandy&Gal (Jan 13, 2004)

elTwitcho said:


> To prevent this I've set up a powerhead at the surface pointing downwards that comes on when the lights come on. It is my hope that this will provide enough surface agitation to prevent CO2 levels from dropping too far as the water should constantly be absorbing CO2 from the atmosphere.
> [snapback]910895[/snapback]​


Im sorta confused by the surface agitation. i always read that the more surface agitation you had going on the more CO2 is released from your tank. So if you had a heavily planted tank would you want the least amount of surface agitation. unless i am reading your statement wrong.


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## elTwitcho (Jun 22, 2004)

Mandy&Gal said:


> elTwitcho said:
> 
> 
> > To prevent this I've set up a powerhead at the surface pointing downwards that comes on when the lights come on. It is my hope that this will provide enough surface agitation to prevent CO2 levels from dropping too far as the water should constantly be absorbing CO2 from the atmosphere.
> ...


It was an experiment I'd set up, that didn't quite work









In a tank with CO2 injection where you have high CO2 levels, you don't want surface agitation because the concentration of CO2 in your water is higher than it is in the atmosphere, meaning your tank is giving off CO2 at the surface. In a lightly stocked non CO2 injected tank, the plants consume most of the CO2 and the CO2 levels are actually lower in your water than they are in the atmosphere. As a result, you wont lose much CO2 to surface agitation since if anything, you'll be absorbing it.


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