# CO2 in a refugium...



## jschall (Apr 13, 2009)

Ok, I have about 60gph running through a 10 gallon refugium. This means that the water is replaced every 10 minutes, give or take.

I want to inject CO2 into this refugium, but I don't want to change the pH of the main tank. In order to keep it from changing the pH of the main tank, I'd probably filter the water exiting the refugium through some crushed coral or similar. I understand I'd be wasting a lot of CO2, but just how much will I need?

I'd want to go pressurized. I don't want a big disgusting bottle of yeast.


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## jmontee (Feb 7, 2008)

> I want to inject CO2 into this refugium, but I don't want to change the pH of the main tank. In order to keep it from changing the pH of the main tank, I'd probably filter the water exiting the refugium through some crushed coral or similar.


Not changing the pH when adding CO2 is not possible, it's chemistry. I think you are trying to control too many variables and adding a lot of headaches. If you have any fluctuations in CO2 then you never know where your pH could end up. If you have good circulation then the pH in the main tank should be the same as the refugium once everything is in equilibrium. 
Crushed coral would continue to increase the pH as it breaks down and there would be no way to really control that process.



> I understand I'd be wasting a lot of CO2, but just how much will I need?


This would depend on the size of the tank and the efficiency of your diffuser/reactor.

My advice would be to use Excel instead of CO2 if you don't want to change the pH. Why do you not want to change the pH, cichlid tank? You could also use plants like ferns, and anubias which do really well at more alkaline pH's and do not require CO2 injection and use lower light.


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## Your Ad Here (Apr 4, 2009)

while researching another unrelated problem of mine, i found a way you could acomplish what you want,
the first is very simple; massive airiation after the fuge, but before the return pump. such as running the water through a skimmer (preferably a recirculating needlewheel or similar)
you just need to outgas the co2, before it hits the tank.
chemical pH regulation with Calcium Carbonate just seems too unstable to me. because you would essentialy be making a calcium reactor by doing so, making for a very unstable pH thoughout the system.

the next will be 100% effective, but require a skimmer an ozone generator and a carbon reactor.

like i said, probably not worth it, for what you want to do.

Chris








but is very convoluted and probably not worthwhile.


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## nokturnalkid (Feb 27, 2007)

What's the use of the refugium? In reef tanks, alot of the time it's used to grow microalgae, in other words, the good algae that takes up nutrients. If you are gonna do something like that, get some duckweed and throw it in there and put some light on it. Duckweed will suck up those excess nutrients.


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## jschall (Apr 13, 2009)

nokturnalkid said:


> What's the use of the refugium? In reef tanks, alot of the time it's used to grow microalgae, in other words, the good algae that takes up nutrients. If you are gonna do something like that, get some duckweed and throw it in there and put some light on it. Duckweed will suck up those excess nutrients.


Its primary use was going to be holding cichlid fry, and then it turned into a planted tank somehow 

I could spend $10 on a tank and pull the hood and plants for a standalone tank. The major expenditure (plants, hood, and bulbs) is out of the way.


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## nokturnalkid (Feb 27, 2007)

jschall said:


> Its primary use was going to be holding cichlid fry, and then it turned into a planted tank somehow
> 
> I could spend $10 on a tank and pull the hood and plants for a standalone tank. The major expenditure (plants, hood, and bulbs) is out of the way.


Hehe...just use this chance to setup another tank.


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