# Co2 and Automatic PH control setup



## Hoppy (Dec 24, 2005)

First, don't worry about pH harming the fish. The pH changes that occur from CO2 dissolving in the water have not been found to harm fish at all. Also, you can't determine how much CO2 is in a typical aquarium by measuring pH and KH. To use the controller you should determine that you have the right amount of CO2 by another method, such as by noting that you get some pearling within a couple of hours after the lights come on, and not so much CO2 that the fish start clustering at the water surface like they are gasping for air. Then set the controller to control to that pH, whatever it is. You can still experience a change in KH, such as by dissolving carbonate rocks in the aquarium or by having Vals or other carbonate eating plants in the tank. That will make your CO2 level change when the controller holds the pH constant. So, you need to observe the tank carefully every few days to make sure you still are controlling to a good level of CO2.


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## Postal Penguin (Mar 30, 2009)

You could leave the pH system on at night and then it will hold the pH steady through the day and night. At night it will still inject CO2 to compensate for the CO2 that dissipates into the air but it will not turn on as much as during the day.


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## binders (Mar 22, 2009)

When I got my CO2 system w/pH controller from Greenleaf, Orlando told me to measue the pH first then set the controller for 1 degree less pH as a starting point. Then fine tune it by watch the drop checker. I would assume that you could also look at the fish and plants. I found this worked for me and I have slightly adjusted it from that start point. I also leave everything running at night so that there is a steady supplie of CO2 in the water when the lights come on in the morning.

Hope this helps. Congrats on getting a CO2 system.


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## blackandyellow (Jul 1, 2009)

Thanks so much, very helpful info. I´ve also read about the bubble counter helping on determining the co2 flow. How many bubbles x second would be a good rate? 

I don´t even want to think anymore about how much I paid for the co2 system... uff that is expensive! but hopefully will be worth it in a few months when the plants are doing great


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## binders (Mar 22, 2009)

Don't know how big your tanks is but it doesn't really matter how many BPS with the pH controller because the controller will turn the CO2 off when then pH gets down to a set level and you will not have to manually control the CO2 by bubble count. Having said that though I would not have it racing in. I do about 2-3 bubbles per second in my 29 and 3-4 in my 80 gal. The drop check is light green on both and I never have had a problem with gasping fish.

Another reason for not having the count too high is that occasionably a solenoid valve will get stuck open and if the CO2 is running too fast the fish will OD and die pretty quickly. At a slower rate there is a better chance of noticing the fish's state and doing something about it before it is too late.

Hope this makes sense.


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## SPECIAL||PLANS (May 27, 2009)

The drop checker seems like a worthwhile investment. Ph alone won't tell you your co2 levels are right. I think...?


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## blackandyellow (Jul 1, 2009)

Thanks for the advice. I´ll get the drop checker in addition to the ph controller, doesn´t seem to be expensive and at this point I´m not going to risk fish for doing something stupid. 

Considering your 80 gal has a 3-4 bps count I guess 5 should be ok for a 100? 

The tank is still not full of plants though, but I´m planning on adding more this weekend. i don´t want to put any fish until the tank is totally stable.


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## blackandyellow (Jul 1, 2009)

Hi all, I have another question about the Co2 injection:

My tank currently has a PH of 6.5, a KH of 1 and a GH of 2, this is without any Co2, Ph is low because of the large piece of driftwood and KH is low because the tank was filled with bottled water.

My question is, since the tank already has a low ph and KH does this mean it has a good amount of Co2? How could this be possible if I still haven´t injected any co2 yet? 

What would happen once I start the Co2 system? since it would be controlled via a ph controller would it be off all the time?


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## dizguy (Oct 29, 2003)

I'm just going to throw this out there and I don't know if it has been tried. I have read that fluctuations in Kh affect the CO2 / Ph formula. Why not isolate a solution of known Kh value like in a drop checker to use with a probe?


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## Darkblade48 (Jan 4, 2008)

blackandyellow said:


> My tank currently has a PH of 6.5, a KH of 1 and a GH of 2, this is without any Co2, Ph is low because of the large piece of driftwood and KH is low because the tank was filled with bottled water.





blackandyellow said:


> My question is, since the tank already has a low ph and KH does this mean it has a good amount of Co2? How could this be possible if I still haven´t injected any co2 yet?


You essentially answered your own question. The tank does not have a good level of CO2 yet, because you haven't injected any CO2 yet. The pH and kH relationship works, provided there are no outside influences. However, in the aquarium, things such as DOCs and other chemicals will affect the kH/pH relationship, thereby skewing the estimate of how much CO2 is in your tank.




blackandyellow said:


> What would happen once I start the Co2 system? since it would be controlled via a ph controller would it be off all the time?


Essentially, the pH controller would read the pH as 6.5, and then turn off once it reached its set point. In most cases, the general thing to do is to measure the pH, and then set the pH controller to 1.0 lower than the measured value (in your case, 5.5) to get a good level of CO2. Since this is quite low, I'd perhaps adjust your pH controller to 6.0 first, and then go from there (i.e. adjust as required by watching your drop checker).



dizguy said:


> I'm just going to throw this out there and I don't know if it has been tried. I have read that fluctuations in Kh affect the CO2 / Ph formula. Why not isolate a solution of known Kh value like in a drop checker to use with a probe?


I suppose this would work, but I think it is overly complicating things. As mentioned, most people just set the pH controller shut off to a pH value 1.0 lower than the current pH and then go from there in adjusting theri CO2 (by observing the drop checker).


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## Postal Penguin (Mar 30, 2009)

dizguy said:


> I'm just going to throw this out there and I don't know if it has been tried. I have read that fluctuations in Kh affect the CO2 / Ph formula. Why not isolate a solution of known Kh value like in a drop checker to use with a probe?


I wouldn't do that, it greatly increases the response time of the pH probe and controller. pH probes can react instantly to pH changes but in that set-up you'll have to wait an hour or two for the pH inside the drop checker to equalize to the tank's pH. With that set-up you'll really just have a fancy digital drop-checker instead of a pH controller.


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## blackandyellow (Jul 1, 2009)

Thanks for the explanation Darkblade, very complete. I´ll start setting the ph controller to 6.0 and see how it works from there, and carefully start adjusting the parameters.


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## talontsiawd (Oct 19, 2008)

I don't have a ph controler but have been thinking about buying one. My theory was to just go off my levels I have set using a drop checker, then if there is an issue, adjust the ph. Seems like the way to go in my mind. Then if you think you need more later with added plants (one reason I am hesitant to do it now), go off the drop checker for reference.


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## blackandyellow (Jul 1, 2009)

I finally started the co2 system on the tank this weekend. I couldn´t find a drop checker in my LFS, but went with the flow of the 4 bps through the integrated bubble counter on my diffuser. The PH level was set to turn off at 6, and anyway I´m turning the co2 off at nights, so by the morning the ph is 6.7. It´s been going down to 6.2.

Yesterday for the first time I saw the amazon swords bubbling! it was exciting! and lucky me... they guy that sold me the aquarium has a friend that cultivates lots of plants so he gave me for free a lot of great plants: a huge aponogeton, several types of cryptos, bacopas, hygros, glossos, microsorum, anubias,etc. Right now the tank looks like a little jungle! 

I´ll see which species develop better and from there start re-organizing the aquascape, but for now I´m loving having so many different species. The swords that were the first inhabitants in the tank seem to be very happy growing new leaves constantly and showing a bright green color, so I hope the new additions catch up too! 

Now I only have to find some nice fish, which seems it´s going to be a hard job


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