# CO2 - immediate changes to chemistry?



## 182 (Apr 21, 2010)

Hey guys. Recently got a CO2 system up and running. Been a few days, and I swear I can already see a difference in the plants.

Unfortunately, I woke up this morning to find a dead Gourami. I'm not entirely sure the two are related (she was looking rather bloaty over the past week, but otherwise healthy) but I was wondering if I should have anticipated a massive chemistry change due to the CO2. I've heard PH drops, but I figured with such a slow rate (1 bubble every three seconds or so in a 72 gallon tank) that the change would be gradual.

I've yet to run tests (was late for work already when I found the casualty) but I figured y'all may be able to give me a little info. Thanks!


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## neven (May 15, 2010)

measure your water hardness to see where its at, with little to no hardness, the PH swings are rather large compared to if your water was properly buffered


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## 182 (Apr 21, 2010)

Will a reef test kit properly measure freshwater hardness, or should I pick up a freshwater specific test?

Thanks!


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## neven (May 15, 2010)

should be the same test whether its fresh or salt

Kh is what matters when it comes to co2. You need a hardness of atleast 3dKH , most aim for 4-6 dkh.

ppm is what the test kit measures in, conversion = 17.8 ppm to 1 degree Kh or Gh


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## 182 (Apr 21, 2010)

Well, historically (I haven't tested in a month or so - ran out of strips) my hardness has been about 4dKH. My SW tank is 4-5dKH.

I'll test again tonight with the proper tests. Thanks again.


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## Kitsune (Jul 17, 2010)

If you are finding that your pH swings considerably, then you have low KH. 
If you are not adding anything to your tank during a water change, then likely your water lacks buffing capacity (You can find issues about the Vancouver water by Rastapus: http://www.bcaquaria.com/forum/island-pets-unlimited-42/water-supply-issue-lower-mainland-715/). I add a pH buffer (don't ask me if its acidic or alkaline...  I'll have to look at my bottle. Chemistry was not my forte).


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## neven (May 15, 2010)

baking soda if its too low, for just KH

1 tsp per 10 gallons of water = around 70ppm KH


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## 2wheelsx2 (Apr 21, 2010)

I doubt if it's the chemistry changes that killed your gourami. Invertebrates are much more sensitive to CO2 levels and chemistry than fish (courtesy of Tom Barr once again) and before I learned about buffered, I never any shrimp to CO2 chemistry/pH issues.

My question would be, are you running the CO2 24/7 or are you using a timer/solenoid, or a pH controller/solenoid? Probably not a pH controller since you're worried about pH swings....


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## 182 (Apr 21, 2010)

It's running 24/7. Tank and regulator.

I'm tending to agree that it's not what killed my fish, but it's rather coincidental. Haven't had a death in about 8 months.


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## 2wheelsx2 (Apr 21, 2010)

I would have suggested CO2 poisoning, except that it was a gourami. I would, however, suggest that you not inject CO2 at night. It's not needed at all, and is not good for the critters since the plants are outputting CO2 at night already.


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## 182 (Apr 21, 2010)

Ah. So in my case, the best practice would be to shut the tank off manually every night? I'm super new to the CO2 game. 

Thanks for all the help/info.


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## 2wheelsx2 (Apr 21, 2010)

Yep, I would do that, or better yet, get a solenoid and put it on a timer to turn it on and off for you.

J&L has them, but a bit pricey: Solenoid Valve for CO2 Regulator

I am sure there are many places to get them locally if you know what you're doing, but I didn't and get mine from Rex Grigg:

The Best Aquarium Regulator & CO2 Parts


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## Captured Moments (Apr 22, 2010)

You said your bubble rate is 1 bubble every 3 seconds or so for a 72 gal tank?
Even if your diffusion of Co2 is highly efficient, I am pretty sure your fish died not because of the Co2 and you also would not be near the required Co2 ppm target range.


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## 182 (Apr 21, 2010)

Yeah, I figured I'd introduce it rather slowly. At least until I get a drop checker in there.


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## 2wheelsx2 (Apr 21, 2010)

Captured Moments said:


> You said your bubble rate is 1 bubble every 3 seconds or so for a 72 gal tank?
> Even if your diffusion of Co2 is highly efficient, I am pretty sure your fish died not because of the Co2 and you also would not be near the required Co2 ppm target range.


I think so too. And given that it was a gourami that died, it's even less likely.


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