# Bubbles in your canister from CO2?



## Phil Edwards (Jan 22, 2004)

Hey folks,

I'm running an AquaMedic Reactor 1000 on an Eheim Pro II 2026 @ 2 bubbles/sec CO2. I've noticed that later in the day/photoperiod the filter starts blowing bubbles of gas from the return. I'm sure it's not CO2 or not much CO2 if there is some, because the amount of gas blown out is higher than the CO2 going in. Also, the bubbles aren't present at night or early on in the photoperiod suggesting that all the CO2 is getting diffused into solution. Have any of you experienced the same thing? 

Thanks,
Phil


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## pineapple (May 4, 2004)

Although not the same as your set up, I have a similar experience with an Eheim 2224. CO2 is bubbled into the filter intake. In my circumstance, the reason is because later in the day the water is saturated with O2 as the plants have been pearling heavily since a little after lights on. Water taken into the filter is saturated in O2 and includes O2 bubbles from pearling plants. In the last hour before lights out, there is significant bubbling from the filter outflow as the oxygen is ejected. I try and adjust this by reducing the CO2 a little.

Andrew Cribb


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## MiamiAG (Jan 13, 2004)

I used to experience this as well. I'm not sure but I think when you bubble CO2, the bubble exchanges the CO2 for other gases present (e.g., N). You then end up with bubble accumulation that may be composed of N, O2, whatever. When this gets to a large enough size, the filter burps it out.

That's how I thought about it anyway.


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## Phil Edwards (Jan 22, 2004)

Thanks guys. 

I was thinking the same thing Art and wanted to see if other folks had the same thoughts. What a PITA that is going to be, healthy plants=ugly bubbles!  That's a first.


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## Jeff Kropp (Apr 25, 2004)

Art_Giacosa said:


> That's how I thought about it anyway.


My unfounded speculation was that my water became super gas saturated. Then when the impeller turned it created a low pressure area behind each blade and my water 'boiled' at room temperature.

However now that I have a separate reactor my cannister no longer belches or rattles. There is no way that my earlier speculation could be correct.

Phil, you will find that a separate reactor will eliminate your belching problem.


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## Phil Edwards (Jan 22, 2004)

I was talking with Neil Frank, who's an air quality expert as well as being a highly experienced aquarist and he said confirmed what Art was saying. As CO2 bubbles diffuse in water they CO2 can be replaced by N2 and O2 and precipitate out of solution to form bubbles. It's highly likely in my estimation that these bubbles are getting trapped in my fine media and congregating until they get sucked through the impeller. Since I spent more money than I probably should have for that reactor I'm going to stick with it and just burp the canister first thing when I get home. 

Jeff, that low pressure idea is a good one! I'll have to talk with my dynamics professor about that one. I wonder how much pressure there is in a canister already? Intriguing.

Best,
Phil


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## Jeff Kropp (Apr 25, 2004)

Phil, 
Can you put the reactor on the return side? That might eliminate the problem in the cannister. Also consider that if your injection rate is set higher than your reactor's ability to dissolve gas it will burp out any excess.


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