# Crazy PH Readings



## Sunny (Aug 26, 2009)

Okay some of you may have been following and helping me with the setup of my CO2. Everything is up and running but my ph is crazy, at night when the lights are off my ph goes up? everything I have read indicates that it should go down, not up. Because the ph goes up, my CO2 does not shut off at all it just runs all night. My fish appear to be healthy and are not gasping for air in the morning. What could it be?


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## Chris S (Dec 19, 2007)

Couple of questions:

Are you using a pH monitor to control your co2 regulator?

Do you run a bubbler at any time?

What are your pH readings during the day and then at night?


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## Sunny (Aug 26, 2009)

Hi Chris no bubblers at all and I am using a ph controller. I did however found out what it was, my bubble rate is high enough to the point where it is hard to count the bubbles, the needle valve was cutting itself back just enough to make the ph go up but not enough that you could see it visually. I have since started to use the main regulator to adjust the flow instead of the needle valve and it appears to be more stable this way.


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## Chris S (Dec 19, 2007)

You should be able to set the working pressure on the regulator itself to around 10-15 (mine stays around 12 or so). From there, you can adjust the needle valve more accurately. You should be using the needle valve to adjust your bubble rate, not the regulator. It sometimes takes a few days for your settings to stay, both on the needle valve and regulator itself. So check a couple times a day, and readjust if needed.

I used to use a pH controller to control my co2 as well, but have since had better results putting the regulator on a seperate timer. This timer goes on an hour before the lights go on and turns off an hour before the lights turn off.

This allows for a proper buildup of co2 for when the plants can begin photosynthesizing, and shuts it off so no co2 is wasted when the lights are off.


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## Jonathan (Oct 16, 2009)

Hi Sunny,
Do you have any calcaerious rocks in your tank, like dolemite or limestone? Its possible that you are creating enough carbonic acid at night that you're dissolving these rocks and raising the pH. 

Adding a buffer to your water will tighten up the pH swings in your tank but I agree with the previuos poster that you should shut the CO2 off when the lights are off. The plants won't use it at night.

I run mine an hour after lights on untill an hour before lights out.


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## Sunny (Aug 26, 2009)

Jonathan said:


> I agree with the previuos poster that you should shut the CO2 off when the lights are off. The plants won't use it at night.
> 
> I run mine an hour after lights on untill an hour before lights out.


I'm using a ph controller set to a ph 0f 7.5, this keeps my drop checker in the green and turns itself on and off when the ph goes out of range. The problem was the regulator not staying set where I put it, but it appears to have settled down now. I suppose it's just CO2 growing pains.


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## Darkblade48 (Jan 28, 2008)

I assume that you are using a 4 dkH reference solution in your drop checker. 

If you are, and your drop checker is green, then you have the ideal CO2 concentrations.

Determining CO2 levels from just a pH meter and a kH test kit is not a reliable method at all. The same can be said for using a drop checker without a 4 dkH reference solution. This is because there are various other buffers (i.e. phosphate buffers) in the aquarium that can contribute to kH, throwing off the pH/kH/CO2 relationship.

As for the regulator not staying set; this is more likely a problem with the needle valve and not the regulator itself. 

What regulator and needle valve do you have? Milwaukee, JBJ and Azoo stock needle valves are notorious for not being stable and requiring frequent readjustments (anywhere from once every few days to everyday).


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## Sunny (Aug 26, 2009)

Hi Anthony yes I am using a KH4 test solution, Orlando at Greenleaf set me up with that and has been a great help. I'm using the Milwaukee dual guage regulator with needle valve and bubble counter which is taking a little bit of time to get it settled down. Unfortunately at this end of town we have extremely hard water KH13 and ph8, but when the drop checker turns green my ph settles in at 7.4 to 7.5 and that is where I set my Milwaukee SMS122 ph controller. I didn't know how to set it up correctly but Orlando went into great detail explaining to me and I now have it at the optimum setting.


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## Darkblade48 (Jan 28, 2008)

Peter,

That sounds about right. If you are using a 4 dkH reference solution in your drop checker and it is green when the pH is 7.5 or so, then set your pH controller there and everything should be fine.

As for the instability of the CO2 flow, as I mentioned previously, this is likely due to the fact that the stock needle valve on the Milwaukee regulator is not the best, and may require frequent readjustments before it settles down.


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