# Excess DIY CO2



## stcyrwm (Apr 20, 2005)

How do people deal with excess diy CO2? I have been surprised how easy it is to generate enough co2 for my 10 and 37 gallon tanks. Of course, the downside to that is regulating the co2. I've dealt with this by just disconnecting the co2 at night or sooner if need be. This is a little bit of a scary job because I am using the EI system which shoots for co2 at 30ppm so if I overshoot then I'm quickly into the 40 plus range which of course gets hazardous for the fish. I like this system though (so do the plants), because it seems to quickly be eliminating my algae problems (smile). 
Anyway I was curious if anyone else is disconnecting their diy co2 at night and if anyone has tried automating it with a solenoid valve that would vent the co2.

Bill


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## czado (May 26, 2005)

Smaller reactor bottle, less yeast with a change before it multiplies, etc would work. If you can keep stable pH at +40ppm CO2 I think you should roll with it -- why not?

2 other easy solutions:
If you're using a powered diffuser, put the powerhead on a timer
Run an airstone at night


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## bharada (Apr 17, 2004)

40ppm of CO2 won't be hazardous to your fish. The easiest check to do is observe the fish just before the lights go on. If they're swimming/acting normal then you have nothing to worry about. If you see them gasping for air at the surface then you should hook up an air pump to a timer to run during lights out. This will outgas excess CO2 when the plants aren't using it. I would have the pump shut off a couple of hours before the lights turn on so that the CO2 can start building back up for when the plants need it.


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## stcyrwm (Apr 20, 2005)

Maybe I'm overanxious but I have a hard time waiting to see if the fish are gasping for air at the surface, so I'm constantly measuring ph and calculating co2 to avoid this situation. Maybe I just need to do the airstone on a timer at night. High co2 doesn't seem to bother the fish in the day. I've had measurements as high as 54ppm with no effect. Of course at that point I disconnect the co2. I'm almost ready to just cut the lights back and not do the co2 or just do low levels.
On the other hand maybe I just need a valium (grin).

Bill


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## bharada (Apr 17, 2004)

If your plants pearl heavily during the day then I doubt that the O2 would be depleted during the night. But if you need peace of mind, run an airstone during the middle of the night for 4-5 hours.


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## stcyrwm (Apr 20, 2005)

Bharada,

I'm still learning all of this so help me sort this out. First off there is no issue with fish and pH swings despite all the warnings to the contrary. This much I think I have absorbed. Now what I'm getting from what you are saying is that high co2 is not really a problem - the problem is low oxygen. So with high co2 the plants will produce enough oxygen during the day and possibly enough for through the night. If I'm worried that it's not enough for through the night then I can supplement that with a bubbler. This means I can relax and not be measuring the pH all the time and I can ignore the bright red high co2 danger warnings in my "Chuck's CO2 Calculator". Am I getting this right? 
I feel like a little like an idiot because this seems like a "no brainer". On the other hand there are so many warnings about pH swings and high co2 that it is a little challenging to absorb what you are saying. Especially when I have a couple gasping fish experiences to back up my fears. Still, I think what you are saying makes sense and I think the times the fish were gasping was before I had the ferts under control and before the plants started pearling. 

Thanks for your help, Bill


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## Simpte 27 (Jul 16, 2004)

Would be interesting to know your CO2 setup.


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## stcyrwm (Apr 20, 2005)

10 gallon has gravel vac tube on outlet of Eheim 2015 (old filter which was given to me) with co2 feeding into this tube and filter material stuffed in end to keep bubble action in tube. I'm not sure why more folks don't use this setup as it is so simple to build.
37 gallon has an old Jungle Fizz Factory diffusion bell about the size and shape of an exra long butter dish cover - 2"wide by 8" long by 2" depth. I have the inlet of an Eheim Ecco filter placed so the current is pulled along the bottom of the diffuser. 
I'm using alkalinity and pH test kits by Hach. I'm not sure I would trust the levels I'm getting except for the amount of pearling I get and because the gasping fish agreed with my testing. 
CO2 bottles are standard double 2 liter setup for 37 and a single 1 gallon for the 10 gallon tank.

Bill


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